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FAQ/Strategy Guide by samuelboyer1342

Version: 1.0 | Updated: 09/21/12

The Binding of Isaac: Wrath of the Lamb Advanced Strategy Guide

This unofficial, unauthorized guide copyright 2012 by Three Fates Games LLC.
The unauthorized reproduction, alteration, publication, sale, or distribution,
without the consent of the author, is prohibited by law. This guide may be
freely downloaded or printed for personal use, but never if such use would
violate the above restrictions.

The contents herein are unofficial advanced strategies for Edmund Mcmullen's
"The Binding of Isaac" video game, and its official expansion "Wrath of the
Lamb", for PC's, Macintosh, and Steam. This guide is based on a combination of
the author's personal experience and common knowledge shared on such websites
as "The Binding of Isaac" wiki site, Gamefaqs, Mcmullen's blogs and other
communications, etc.

This guide is not meant for players new to The Binding of Isaac and The Wrath
of the Lamb: it assumes the player has total familiarity with the basic rules
and mechanics of the game and so will not further explain these concepts
except when necessary. This guide will enhance your play of the game, help you
defeat the bosses and some of the trickier enemies regardless of the items
that you find, use your resources to their maximum efficiency, and maximize
Isaac's sad, terrifying life.

Comments and questions can be directed to:

Minimizing Risk and Maximizing Gain

Tip #1: Knowing what a floor will contain

In every level ("floor"), the layout of the rooms, and what rooms will
contain, is randomized, barring certain exceptions that are ALWAYS present.

-Levels 1-6 ALWAYS contain a shop and item room

-All levels contain both a secret and top secret room, and a boss room

-Level 1 will NEVER have an arena, arcade, OR devil/god room. It is
unconfirmed that level 1 will NEVER have a library.

-Levels 1-9 (9 being Sheol of Heaven) MAY contain any or all of: sacrifice
room, cursed room).

Levels 2-9 MAY also include: library, arcade, arena (regular or boss type

-Levels 7-9 will NEVER contain a shop or item room. They will rarely have a
cursed room, library, or arcade. They more often contain a sacrifice room or
arena, but there is no guarantee that either will appear.

-Level 10 (the chest) has no special rooms except the starting area containing
4 gold chests and the boss room (although glitched secret rooms can appear)

-Levels 1-10 ALWAYS have a boss room

Given all of the above, planning a long term strategy for TBoI is impossible:
you cannot predict what items you will get, whether any optional rooms will
appear (I have gone entire runs without seeing an arcade on occasion), whether
you will have the bombs (and intuition) to open the secret rooms, or what
bosses you will fight.

Once you KNOW what a floor contains, however, you can make the best plays to
maximize the amount of loot you can carry out, and thereby increase your odds
of making a complete 10 level run (assuming you have unlocked the Polaroid,
which you can do by completing Heaven with six characters). Good reflexes and
footwork can get you very far in this game, but unless you have the senses of
Spider-Man (or play video games far too much), you will need every tool you
can get.

Sometimes, you will get unlucky and have to slog through a cursed floor. You
could receive one of four curses, which are:
1)	Curse of the Labyrinth, which doubles the floor's size, gives you two
item rooms (if levels 1-6), forces you to fight 2 bosses, and (although
it is a glitch) makes secret rooms useless, containing enemies like any
other room (Top Secret Rooms act normally). You can only receive Curse
of the Labyrinth on levels 1, 3, 5, and 7. Curse of the Labyrinth is
more irritating than outright dangerous, except if it appears on level 1
or 7. If it appears on level 1, you will have to unlock BOTH item rooms,
meaning you must hope keys spawn on the level. If the curse appears on
level 7, you will have a much harder time getting to the Boss rooms
quickly, making death a much greater possibility in this high-damage,
low-heart environment.
2)	Curse of Darkness prevents you from viewing the mini-map, even if you
have the map, compass, or use other methods that normally enhance the
mini-map. Curse of Darkness makes finding the secret and top-secret
rooms almost impossible, except by blind (pun intended) luck. It also
makes finding the boss room quickly very difficult. To prevent getting
turned around, I recommend grabbing a piece of paper (graph paper is
especially nice) and penciling a map of the floor as you go. By doing
so, you can actually determine the secret room normally, once you have
found every room on the floor.
3)	Curse of the Lost makes the floor one size-category larger than normal
(so levels 1 or 2 are sized as if they were levels 3 or 4). This is the
lightest of the curses overall, and you will often find that the
difference, while significant, is not enough to change your game
4)	Sometimes, the Item room will not spawn on a floor. This is a very rare
curse that seems to show up when your Luck stat (an invisible stat
between -7 and 7) is very low; it has occurred to me on two occasions
when I had my luck dropped by various circumstance.

There is nothing you can do to reverse a curse you have received: just bear
it out as best you can. Curses make the game slightly more challenging, but
are rarely fatal. Multiple cursed levels in a row make the game MUCH
harder, however: try doing the "7 years bad luck" challenge and you will
see just HOW hard.

Tip 2: Maintaining Consumable Inventory

Your consumable inventory is all the items you have available to spend to
increase your inventory as you progress through the levels. The items in your
inventory are: your coins, your bombs, your keys, and your hearts. All four
are paths toward the passive, activated, and familiar items you need to have a
successful run.

Below, I will outline key items each resource can provide you with, and how
you should spend them to get maximum benefit. The rule of thumb: avoid using
your consumables unless you ABSOLUTELY HAVE TO until you have cleared the
level and can return to rooms at your leisure. Also, being conservative with
all spending is the name of the game in Binding of Isaac: do not spend
consumable items with the hope of using an item in combination with an item
you do not already have. For example, do not buy the Habit if you do not have
a spacebar item you want to be using multiple times in a room; buying it "just
in case" you find such an item is more often than not a waste of coins, or
other useful consumables. If you treat hearts so cavalierly, your run will be
a quick failure.

Coins: are primarily useful for exchanging into the other three resources.
Running coins through slot machines, fortune teller machines, bums, and the
store, can get you plenty of bombs, keys, hearts, soul hearts, trinkets,
cards, pills, and even MORE coins. The trick is knowing how many coins to
spend, and for what.

In the first two levels, unless one gets very lucky and has a massive surplus,
one should not spend coins at all. The various machines and bums are very rare
in these levels, and often one will not have enough keys to make use of the
store. Even in the third and fourth levels, one should concentrate on
squirreling together coins unless one has at least 10-20 and enough keys to
enter the shop and not miss the item room. The first reason why you should
only enter shops when you have plenty of coins is because entering the shop is
simply wasting a precious key if the store has nothing you can afford: going
into a store hoping to see an item on sale is folly, as the odds are quite
low. The second reason is that, coin for coin, the shop is often a very
expensive way to increase your inventory items compared to the various
machines; on most runs with average luck, machines can equal or better the
prices you can find in stores, and the machines can be exploded to recoup part
of your investment if the machine proves stubborn.

If one has plenty of coins, and extra keys, one should STILL avoid going to
the shop until the entire level has been cleared out. Doing so guarantees that
you do not pass up a bum or an arcade: once you know what else is available
for spending money, then you can consider spending a key to enter the shop,
bearing in mind that Greed might ruin your shopping spree (although if he
drops Steam Sale or a Quarter, it is more than worth killing him).

In the shop, carefully consider whether or not buying the major item is worth
the coins AT THAT MOMENT. Say the major item on sale is the 9-Volt; if you do
not have an activated item, or have one that charges in one or two rooms, the
9-Volt is completely pointless and a waste of your money. Likewise, Mom's Bag
should only be bought if you ALREADY have a trinket on hand, and it is early
enough in the game (before level 6 minimum) that you would likely run into
another trinket. Mom's Coinpurse is a sure buy for anyone playing Cain, but if
you have gotten three bad pills in a row, it is quite likely that at least
half of the pills that you get from the Coinpurse will be useless or downright
bad for you. Bum Friend is a dubious item at best, but if it is Level 6
(meaning other spending options are going to be limited), it could be a
lifesaver if it drops a heart or useful tarot card.
Some major items are great pick-ups no matter what your situation; the compass
and map in particular can save you plenty of headaches and lost life in levels
7+. They are always worth your money, and if you can get both at the same
time, you can easily skip straight to bosses almost as fast as if you had an
Emperor card!

If you spot a Bum, make sure to clear the floor out EXCEPT FOR THE BOSS and
get every penny that floor can give you. Bums tend to pay out with a major
item after 5-15 coins, and they are a great boon: unless the shop on that
level has an item you cannot pass up, use your coins on the bum. Bums are also
great for acquiring consumables because they are GUARANTEED to produce one at
least every 5 coins (making them more random, but cheaper, than stores). If,
however, the Bum bankrupts you, or you simply have no coins, blow it up with a
spare bomb; it's cathartic if the Bum never paid out, and it significantly
increases the chances of the Devil Room appearing after defeating the boss.
The Arcade is the place to go for those heavy with change. One can get three
major items in an arcade: blood bag or IV bag from the blood bank, skatole
from the shell game, and a Dollar (and maybe good pills or pretty flies) from
the slots or crystal ball (and trinkets, soul hearts, and cards) from the
Fortune Teller machine. Before you hit an arcade however, clear out the ENTIRE
floor first, including the boss room: using the blood bank counts as damage,
and taking damage on a floor significantly reduces the chances of seeing the
Devil or God room. Clearing the floor also ensures that any heart pick-ups you
did not need are lying around for only one purpose: giving you more chances of
scoring at the blood bank.

In the arcade, walk in with full health. Spend hearts at the blood bank until
you hit the point when you can EXACTLY recover yourself to full hearts by
getting heart pick-ups around the level (players who are supremely confident,
or have lots of soul hearts, should feel free to spend hearts until they are
at half a heart). Then, take your extra coins (you hopefully got 6 or more),
and start playing slots and the shell game in rapid succession. Bounce back
and forth from these games, and every time you get hearts, dump them back into
the blood bank for more coins. With a little bit of luck, on a character with
about 20 coins after first spending hearts at the bank, you should get at
least one, and maybe two or all three, of the major items in the arcade.
Why bother? Because every item in the arcade you get contributes either to
your long-game success or directly helps you get more arcade major items. The
IV Bag can be used in rapid succession by tapping quickly on the Space bar:
you will often get 2 coin awards for every 1/2 heart, greatly boosting your
money. The Blood Bag gives you another heart container and heals FIVE hearts,
making it well worth your investment. Skatole is a lifesaver on late levels,
when flies can be fatal distractions (and boom flies even more so). The dollar
can ensure that you will never run short of the other consumable items as long
as there is SOMETHING to spend money on (goes great with the Portable Slot
from the shop), and the Crystal Ball acts like a World tarot every 6 rooms
(thus voiding the need for map and compass) and provides you with soul hearts
and cards. EVERY item in the arcade is worth the time and money, and provided
you spend your coins frugally, they are not hard to get.

A last note on coins: when given the choice to spend coins on a fortune-
telling machine, or a slot machine, pick the fortune machine unless you are in
dire need of bombs, keys, or hearts: the fortune machine has more substantial
rewards to offer on average, and it produces the Crystal Ball more often than
the slot machine produces the Dollar.

Bombs: are your ticket to riches, soul hearts, and major items. Bombs are the
most common, and easily accessible, way to get into the secret and top secret
rooms. Bombs are also a useful damage buff to you in late levels, when your
attention should be focused on killing the boss and moving on as quickly as

The priority for using bombs is: on dark "X marks the spot" rocks; in order to
access vital pick ups (such as a key to get into the item room); in order to
get at silver chests (or gold ones if you have extra keys); in order to access
the Secret Room; in order to access the Top Secret room; and in order to get
at pick ups you do not seriously need.

While it is true that the rewards in the Secret and Top Secret room are often
very good, "X" rocks are the best thing to spend bombs on, because they will
nearly always produce at least one soul heart (which in advanced runs are
often your only real health) AND they can drop chests (which often contain
major items in this context) OR a Rock, which is a fantastic major item to get
for something as cheap as a bomb. Even if you KNOW where the secret room is
(because of the map, perhaps), save your bombs until you are sure you won't
run out before reaching "X" rocks. Once you do so, feel free to raid the
secret room at the cost of pick ups or chests blocked off by rocks.
In general, a bomb is not as important as a key in levels 2-6, because keys
open item rooms. Therefore, if you have to drop to 0 bombs to get a key you
need, do it. Silver chests contain all manner of pick-ups, often including
more bombs, so they are usually worth your while to obtain; gold chests are
riskier due to the key cost, but could contain a major item, which makes them

Finally, if you have exploited all the other things, you could spend some
bombs trying to find the Secret and Top Secret rooms. In general, the Secret
room can be found adjacent to several other rooms; if on your map you notice a
conspicuous empty cell in between three or four rooms, there is a good chance
it is the secret room. It is far from a guarantee, however: I often find that
the secret room likes to trick me. If you find it, great; if you search and
search and find you have only 1 or 2 bombs left, save them for the next floor.
The Top Secret room is almost impossible to find without getting lucky.
However, it is usually off on the edges of the map, adjacent to only 1 other
room. If for some reason the room is adjacent to more than one room, only ONE
of those rooms will have the access door, unlike secret rooms which can be
entered from any available wall. The Top Secret room is often not worth your
effort, but if stumbled upon quickly, its small rewards can be quite nice
(best thing you will find is an Eternal Heart).

Avoid wasting bombs on getting a couple of coins; use a bomb in such
circumstances if you have plenty extra, or if you are only a few coins away
from a much-desired shop item or arcade run. If the coin is a nickel or a
dime, it may be worth doing so on principle, but make sure you have spent
bombs on all the best targets first.

Once you reach levels 7+, bombs lose their utility value. On these levels,
pick ups and chests do not usually spawn in blocked off locations, and "X
marks the spot" rocks are extremely rare (and often no longer marked). Spend a
bomb or two if you have extras if you know where the secret room is (or have a
good guess). Do not bother hunting down the Top Secret room unless you are
truly desperate, or have a massive cache of bombs and have cleared most, if
not all, of the level (which you should NOT be doing if possible: clearing
floors after level 6 is too risky). Save your bombs for attacking difficult
bosses, whichever ones you have the most trouble with (I like to have them
around for Carrion Queen, Satan, Conquest/Headless Horseman, The Bloat, or
even Mom's Heart/It Lives if I have plenty and want to speed the fight up). On
levels 9 and 10, consider using bombs to skip fights if you know which way the
boss is (since room fights in levels 9 and 10 are often more dangerous than
the bosses are).

Keys: are one of your most valuable, perhaps MOST valuable, expendable
resources in levels 2-6. You MUST always ensure you have a key to enter the
Item Room on a given floor: never spend your only key on a gold chest or the
shop, and even if you have cleared the floor and have a single key, strongly
consider just keeping it so you can guarantee access to the Item Room on the
NEXT floor.

On level 1, you don't need a key to enter the item room, and you likely do not
have enough coins to bother going to the shop; therefore, if you find a key
here, count yourself lucky and keep it for level 2.

After level 6, keys drop off dramatically in value. Use them whenever you get
the chance, as it will almost always be to open Gold chests. The game seems to
love throwing surplus keys at you starting around level 6, so go nuts. If you
are making a Chest run, keep at least 4 keys past level 6 so you can get
access to all the items in the first room of level 10.

After opening the floor's item room, use keys to open the Library: Book of
Belial and Book of Shadows are two of the game's best activated items, and
they often appear here. Book of Sins is all right if you have nothing better,
and Dead Sea Scrolls and Bible are just fun (Bible is particularly useful if
you have trouble with Mom, as many players do if they do not know her attack
pattern very well). Book of Revelations is great if you want a Meatboy, or if
you have an item-charge character build for farming Soul hearts, but should be
avoided otherwise, as fighting Harbringers is bad news if you are not trying
to build at least a level 3 meat boy.

Hearts: do not often strike beginners as a resource to be spent; they are
struggling to stay alive, and are stingy with their life. Advanced players,
however, must learn to view hearts as a valuable resource like any other: the
only difference is that you must learn how many hearts to spend.

First of all, never, EVER spend hearts until you have cleared the floor of all
hazards: you will feel very stupid the first time you go bananas on a devil
bum, get unlucky with pay out, and then get killed by a Pooter in the next
room. Second, avoid spending a lot of hearts unless you have soul hearts to
make up for it: as a rule of thumb, I happily spend 1-2 hearts if I have 1
soul heart, 2 hearts if I have 2 soul hearts, and drop myself to 1/2 heart if I
have 3 or more soul hearts. If you are on level 6, avoid spending more than a
heart or two unless you know you can get heart pick-ups to heal: on levels 7+,
stop spending hearts, as they are now too valuable and the rewards almost
irrelevant. Third, unless you are very confident, only spend as many hearts as
you know you can make up with pick-ups in the same floor.

What should you spend hearts on? After beating the boss, consider your first
purchase to be Devil Room items. Devil Room items are a blessing for advanced
players, because while losing heart containers hurts, the best items in the
devil room pay for themselves in terms of damage output and damage avoided. In
addition, spending hearts in a level often counts as taking damage on the
floor, which greatly lowers your chances of seeing the Devil room.
The best Devil Room item, in my opinion, is Spirit of the Night, assuming you
cannot already fly or fire spectral tears. Spirit of the Night gives you BOTH
flight AND spectral tears, allowing you to hover over pits and rocks and fire
at enemies with impunity. In the long run, this item combination can save you
from dozens of hits.

The Pact is also a great Devil Room item, as it gives you a HUGE stat boost
AND provides some Soul Hearts to make up for the container loss.
NEVER buy We Need to go Deeper unless you want to fill your treasury list;
after ten play throughs, you can ALWAYS go to Sheol or Heaven if desired, and
thus the item either deprives you of a much-needed Boss item, or is utterly
useless. For those who are not confident of passing through levels 7 or 8, and
really do not care about missing the item on level 7, then by all means, buy

Items like Brimstone and Guppy's Paw should be well considered, but not bought
impulsively. Brimstone is a notoriously glitchy item with a lot of peculiar
synergy issues, not to mention the charge is a LONG one when you are under
heavy attack. Guppy's Paw is great if you have excess hearts, as it just means
having surplus Soul Hearts (3-1 is a very good ratio). If you only have 3-4
hearts, I would not recommend buying Guppy's Paw, as the extra Soul Hearts at
such a low health level cannot quite compete with the easy refillability of
normal heart containers. If you have 2 hearts, or 1, do not buy Guppy's Paw
(but it might be interesting to do so if you have Guppy (Dead Cat); 3 soul
hearts per life is much better than 1 heart per life)

Whore of Babylon is not terribly useful unless you are ??? (in which case buy
it if you can have at least 2 soul hearts remaining) or can ensure you can run
around with 1/2 heart and not get snuffed out. If you can make the bonus
basically permanent, by all means do so: just be sure not to absently pick up
a heart if you are using a soul heart buffer, since if you cannot find a Devil
Begger or Blood Bank, you'll be stuck. If you can buy both Guppies' Paw and
Whore of Babylon at once, the combo may be worth your while.
All the other Devil Room items are worth thinking carefully about, but do not
buy any of them simply because you can. A Quarter will do you little good if
you already have good Shop items or have raided an arcade, and activated items
for the Devil room are often lackluster for the cost (with the strong
exception of Book of Belial). Familiars like Brother Bobby and Sister Maggy
could be good picks if you are assembling a Family run, but my opinion of
familiars is that they are nice boosts, but will not often save you the hearts
you spend on them.

After dropping heart containers on the Devil room, spend some health on Devil
Beggers. These guys are expensive, so make sure you can recover the health
somehow; they seem to like screwing you more than regular Beggers do. However,
any major item they drop is bound to be worth it.

Next on your list should be Curse rooms. The 1 heart cost is fairly low, and
if you can fly, the cost is only 1/2 heart. Very often, the red chest will only
contain spiders or troll bombs, but any good thing you get out of a red chest
is worth it. Make sure you can recover the heart you spend in case you get
nothing good for your troubles. If you have even 1 soul heart, do not go into
this room unless you can fly; the soul heart is almost always more valuable
than what you get in the red chest(s) (occasionally however you'll get MORE
soul hearts).
Blood banks are a great place to spend excess hearts, but they can be
expensive for this purpose. Be careful not to overspend, and do not chase a
blood bag unless you know you can recover hearts you spend. If you have an
eternal heart, do NOT use the bloodbank: you will lose the heart.

The last place to spend hearts is the sacrifice room. This room is to be
avoided unless there is nothing better to spend on, and you can recover
yourself fully. The sacrifice room LOVES to drain you to just 1 heart before
spawning its chest, if at all, and it takes away soul hearts first, which are
NEVER worth what you get. If you have plenty of heart pick-ups lying around,
no soul hearts, and nothing else to spend your life on, go ahead and see if a
chest appears.

Tip 3: Move!

In the martial arts, there is a saying regarding the virtues of various
defenses: "block before you absorb; parry before you block; dodge before you
parry". This saying holds true to BoI: if you can avoid getting hit, you will
always triumph in the end. However, eliminating enemies quickly is very
useful, and can get you out of bad situations. Attack is very important in
BoI, but not as important as movement, and if you take the offensive at the
wrong moment, or maneuver improperly, it will not matter how strong your
offense is: you will still lose.

Before you move, you must think. Right before you enter a new room, mentally
prepare yourself to encounter a new challenge. Then, when you enter the room,
take 1 second to analyze the space and assess the situation; during this
second, enemies will not attack. Take into account all of the following, in
1)	Are you cornered?
2)	How much room do you have to maneuver?
3)	What are the dangerous features of the room? (stray rocks that could
trap you, fires, spikes, turrets, etc.)
4)	Where are the enemies?
5)	How many enemies are there?
6)	What KIND of enemies are they?
7)	What can you use to your advantage?

The first question is the MOST important; sometimes, you will enter a room on
a single-file pathway, and if this is the case, you MUST get out of that
corner, immediately! Sometimes there will be two single-file pathways, along
both of which Gapers are coming for you. In this situation, you MUST charge to
one side or another and eliminate a Gaprt so you can get into the open. NEVER
allow yourself to be in a situation in which you are unable to move away from
your enemies, and if you are, your first and only priority must be to get out
and get free.

The second question is a tactical matter of life and death. Each room has its
own layout, and in general, layouts that prevent you from moving freely and
openly work against you. If possible, stick close to the edges of rooms to
maximize your free space, as well as distance from your enemies. Do NOT
actually hug the walls; this will put you in corners, in which case you only
have two directions of movement available. Ensure that you can move in all
four directions at all times, if possible, so that you can evade enemies in
whatever direction is most advantageous to you. In general, the most
advantageous direction to dodge is the one in which there are the fewest
enemies that can attack you, and the most free room to continue to maneuver
and dodge.

The third question keeps you aware of these problems, so you can avoid hurting
yourself. If there are turrets, you know that you cannot stand still for long;
if there are spikes, then there are parts of the room that are off-limits for
dodging. Be aware of these dangers so they do not hurt you in a crucial

After these three issues of movement, you should now consider where your
enemies are in relation to your starting position. Have the enemies spawned
close to your position? Are they in front of you? Are they stuck on platforms
surrounded by pits? Knowing the answers to these questions will allow you to
determine the best routes to dodge and maneuver, and how much time you can
allow yourself to destroy your targets.

Next, you should consider how many enemies you face. If only a few, you will
have more room, and can clear the room quickly; if there are many, they can
crowd or surround you. Plan your attack accordingly, keeping in mind that to
escape being surrounded, you should focus on the enemy that blocks the way to
the MOST free space to retreat to.

Then, consider WHAT the enemies are. This is the first step in which you
consider your method of attack; are they Hoppers, is it a Boss, or are they
merely flies? The type of enemy will dictate how you attack them, how much
damage they will take, and how they will attack you. However, if you followed
each of the steps up to this point, how your enemy attacks will only matter
circumstantially; you will already know where you should be and where to
maneuver to.

Finally, consider what your advantages are. Can you manipulate an exploding
turret (or exploding enemies) into destroying enemies for you? Are your foes
trapped and helpless on small islands? Do you have a ready space-bar item that
would be very helpful in this room? Do you have lots of excess bombs you are
itching to detonate? Once you determine your advantages, apply them to defeat
your enemies.

When you have enough experience going through these 7 steps, you will be able
to accurately assess how threatening a room is within that 1 second the game
allots you. If you cannot complete at least up to step 5 in that second,
consider quickly pausing the game to allow you a moment to think everything
through: there is nothing shameful in pausing the action and developing a

When you reach level 7 and beyond, consider one more step: "can I beat this
room without getting hurt?" In levels 1-6, you should always clear EVERY room
to maximize your pick-ups; in later levels, pick ups are rarer and less useful
to you. If you determine that you will probably take a lot of damage before
you clear a room in these late levels, try escaping the room by bombing the
door you wish to proceed through; this tactic is especially viable in Sheol
and Heaven, and if you know where the boss room is, can save you much time and

Tip #4: Coping with Space Bar Items

Space Bar items are, generally speaking, inferior to passive and familiar
items. Their limited ammunition, lack of static bonuses, the fact that you can
only carry one at a time, and their often highly specific or skill-based uses
make them challenging to utilize effectively.

There are ways to maximize the utility of space bar items however, no matter
how many you get, or how peculiar or useless the item appears to be. This
guide will not index the many items and rate them, but it will provide some
guidelines to use them effectively.

1)	If you can use it once a room, use it once a room
Even apparently pointless items, such as the bean or poop, have one
advantage: they can be used in every room you come across. Poop can be
deployed as projectile cover or as a blockade (particularly useful against
Gurdy; see boss strategies), while the bean can be used by the clever and
quick to poison tough melee enemies such as Knights. Remember, however,
that your primary concern is defense: do not force the use of "every room"
items if you cannot do so safely (such as placing poop in such a way that
it prevents you from escaping a foe)

2)	If you can use it every 2-3 rooms, do not be afraid to use it when it is
Spacebar items that can be used every 2-3 rooms, such as the Book of
Shadows or Book of Belial, should be used judiciously. With items that
charge relatively quickly, the more rooms you go through without using the
item, the less chances you are getting to use the item, and thus the harder
you are making the game for yourself. One must be careful, of course: using
The Hourglass in a room with a couple Pooter flies and plenty of space to
maneuver is generally wasteful. Generally speaking, every 2-3 rooms you
will find a group of enemies against which your spacebar item will be quite
helpful: if you see such opportunities, use them, on the off chance that
you would otherwise make a simple error and take a little damage.

3)	If you can use it every 4-6 rooms, be careful
Spacebar items that have a longer charge time are typically very powerful,
such as The Gamekid or The Dead Sea Scrolls. Six rooms is a deceptively
long time to build an item's power up, however: on even XL floors, you can
only use such items perhaps 3-4 times, and often you will find that getting
even 2 uses out of such items is a rarity. Use such items when there is a
VERY clear advantage to doing so, such as using The Nail to smash your way
into a Boss gauntlet room, or save it for the boss, which can help you
eliminate them especially quickly and easily.

4)	If the item can be used without clearing rooms, consider using it then
leaving it.
A very few items, such as Guppies' Paw or IV Bag, allow you to use them at
any time. These items almost always require payment with some resource,
typically hearts, which can make using them very problematic. These items
will rarely help you more than other space bar items, but they CAN be
useful in the level they are found in: IV Bag, given some hearts lying
around, can provide you with some quick money. Blood Rites, Kamikaze, and
Razorblade should be used in reaction to an inevitable hit by a foe
(essentially becoming reflex-based counter attacks). If you have no other
options, by all means, carry these items around; but do not hold them in
favor of other space bar items unless you have a precise and pressing
reason to do so.

5)	If you have a choice between spacebar items, attack is often the best
This rule seems to stand contrary to the general principle of BoI (that
defense trumps offense). However, defensive space bar items are very rare,
and recovery-based space bar items often have long charge times and provide
little in return: the Yum Heart, for example, only heals 1 heart every 6
rooms, which is a poor rate, particularly if you avoid taking damage as you
should. Just as the saying goes, "a penny saved is a penny earned", "a
heart saved is a heart recovered", and SAVING hearts is actually far
preferable to RECOVERING them: not taking damage at all means being able to
use your hearts as a resource more often, going to more Devil/God rooms,
and maintaining a psychological state of control.
Thus, based on your judgment of the relative power/weakness of spacebar
items you find, take strong attack-based items over recovery items: they
will save your life far more often than recovery items will.

Tip #6: Your character

Your starting character in BoI does not often matter very much past the
first four levels: by that time, if you have been crafty and have been
using your resources to the fullest, characters are pretty much the same.
In the early game however, character choice can drastically change how you
play, and some characters have a profound flavor throughout a run of BoI.
Below, each character will be outlined, and given subjective ratings based
on their starting statistics, their starting items, and overall full run
viability, based on a rating from 1 to 10.

1)	Isaac
Isaac is a well-rounded character with no weaknesses. He has the second
highest starting health of any other character, making early devil-room
deals viable, his starting bomb gives him early access to "X" rocks and
secret rooms, and once he gets to start with the D6, he gains control over
the item-generation in the game, which is enormously helpful.
Starting Statistics: 9 Isaac's large health pool and lack of weaknesses
means that he will rarely end up in situations he cannot cope with
effectively. Even if his statistics do not upgrade for as many as 4 levels,
Isaac players will not often encounter situations they are simply too weak
to overcome.
Starting Items: 4 at first, 9 once D6 is unlocked. Without the D6, Isaac's
starting bomb can still provide good bonuses if spent correctly. In the
lucky event that one gets a Rock for their bomb, the bomb will have paid
for itself five times over. However, bomb utility is quite random, in that
bombs cannot be spent as readily or quickly as coins, nor are as obviously
necessary as keys, and do not provide the same bonuses that hearts can.
Once Isaac gets to start with the D6 however, players can quickly rack up
extreme power from the very first floor. ANY major items can be re-rolled,
including shop items, meaning that ALL of your resources can be spent more
effectively, and that you can slightly control what sort of upgrades Isaac
gets. Arguably, there is no better starting item than the D6 for the sheer
control you gain from it. One warning however: you cannot reroll the
Harbringer's Cubes of Meat (though if you reroll other major items that
spawn with the Cube, you can get more).
Viability: 7 without the D6, 9 with it. Isaac's starting statistics are
strong, and any items he encounters can be helpful to him. With his D6,
unneeded spacebar items can be eliminated, superfluous items removed. Isaac
will steadily gain power and likely be able to dominate floors until level
7, at which point the D6 will lose power when the item count drops. It is
possible to get stuck with the D6 as well, if an appropriate space-bar item
is not chosen before floor 7, and this makes maximizing the D6's utility
difficult. Despite this problem, Isaac is still probably BoI's best
starting character, which is only fitting for him being the titular hero.

2)	Cain
Cain is the next-most balanced character after Isaac. His speed is high,
and he has good attack and average rate of fire. His range is low however,
and his 2 heart starting health makes it hard for him to use them as a
resource well early on. His starting item load out is second only to
Isaac's D6, and before Isaac gets the D6, is superior to other characters.
Starting Statistics: 8. Cain's high speed is very useful for dodging
attacks, and generally makes up for his low attack range. His 2 starting
hearts is not great, but not bad, and keeps him alive for a while. His
eyepatch creates some peculiar issues, such as not being able to use items
like technology 2 as effectively as other characters, and makes attacking
enemies from his blind side slightly more difficult (though typically not
in a way that most players will notice.)
Starting Items: 9 Cain's key is a wonderful starting item, as it is not
uncommon to go through levels 1 and 2 without seeing many keys. The
Luckfoot affects a variety of things: it makes all pills he picks up
positive (a great boon), it increases his odds at the Shell Game in the
arcade to almost 50% (rather than 33%, making getting pick-ups and Skatole
more cost-effective), it boosts his successes at all the slots, and makes
curses occur less often. All these bonuses add up quickly, and make Cain
play sometimes feel downright easy when a good run of luck comes.
Viability: 8. While Isaac with the D6 can outstrip Cain, without it Cain's
Luckfoot, high speed, and key make the difference. The Luckfoot is really
Cain's best asset, making even the Womb floors less difficult if an arcade
spawns there (and it seems to quite frequently). However, his eye patch can
occasionally create problems for Cain that only he can suffer from, and his
low starting range, if not repaired, can make defeating some enemies much
more challenging (such as Knights and Mom). Cain is an excellent choice for
players who have a solid understanding of the game.

3)	Magdalene
Magdalene is built to last. She has the highest starting health of any
other character, and starts with the "Yum Heart" space bar item to further
increase her staying power. This makes Magdalene excel at using her hearts
as a resource, making an early or even multiple Devil room exchanges quite
viable, and she can even use Sacrifice rooms somewhat effectively, a trait
no other character can naturally claim. Her starting statistics are
generally average as well, with the exception of speed, which is
unfortunately the worst of any character. She also starts with no resource-
type items except her enormous health pool.
Starting Statistics: 7. Magdalene's high health is a valuable asset, and
her otherwise normal statistics boost her further. Her poor speed can be a
significant liability to her, however, because it makes dodging attacks
difficult. One can expect to get hit more often while playing Magdalene,
which sadly makes it less likely that she will find Devil rooms to spend
her excess hearts in, and also makes her more vulnerable than low-health
characters in levels 7 and beyond, in which getting hit is far more
devastating than not being able to take hits often.
Starting Items: 4. In early levels, the Yum Heart will often not need to be
used at all, although it can help with accessing Curse and Sacrifice rooms
or gambling with a Blood Bank. In late levels, the 1 heart of healing is
often insufficient to make a real difference to one's survivability, and as
a space-bar item, the Heart must compete with other space-bar items that
can make it obsolete.
Viability: 6. If Magdalene can get early speed boosts, she can gain great
power compared to the other characters by using her hearts more often, for
more profit: hearts lead to some of the best bonuses. Without those speed
boosts however, Magdalene will slowly but surely get pressured more and
more by the quick and numerous enemies of later stages, and will likely
meet her end on the bottom of Satan's hoof. Magdalene makes a great
character for beginners having trouble beating Mom or Mom's Heart, but for
those who want to consistently tackle levels 9 and 10, she is not a strong

4)	Judas
Judas is the glass cannon, and tremendously exciting to use as a result. He
has average statistics all around, except for attack, which is enormously
high, and health, which is a paltry 1 heart. Judas' terrible health makes
even entering Curse rooms impossible, and often makes Devil room purchases
equally impossible, not to mention that even a single mistake can end a
Judas run instantly. For those with the skill, and the luck, Judas can
still turn into a killing machine without peer.
Starting Statistics: 5. Judas' strength and weakness is highly apparent:
every room Judas enters is a quick, frantic, and brutal struggle to the
death. He is just fast enough to avoid being hit by most enemies easily,
however: when playing Judas, if one focuses on dodging above all else, one
can get quite far. One mistake, of course, means game over.
Starting Items: 7. Judas' three coins do not seem like much, but a few
extra spins of the fortune telling machine can be highly beneficial to
Judas, not to mention three coins being 20% of a major item in the shop, a
significant boost in that regard. The Book of Belial is one of the best
space-bar items in the game, providing a multiplicative damage boost
(meaning it is always useful even with maxed attack) and larger tears,
along with a fairly quickly recharge time of "every 3 rooms", making the 9
volt a hugely valuable piece of synergy.
Viability: 6. If Judas get a few health-boosts, or just a solid padding of
Soul Hearts, every offensive-boosting item he gets can be used to
devastating potential. His starting offense is strong enough that it is
actually completely possible to never have it upgraded at all: you will
find that Judas can still destroy enemies quickly. If Judas does not get
health boosts however, his demise is inevitable. Judas is a great choice
for players looking for a thrill, but for unconfident or conservative
players, should be strictly avoided.

5)	Eve
Eve is a technical character. She has two passive starting items, Whore of
Babylon and Dead Bird, and high speed, making her a hit-and-run character
mixed with devastating power as she takes damage. Her base attack is the
worst in the game however, and she has only two starting heart containers.
Her lack of consumable items, and the unreliable nature of her starting
items, makes her a challenge to use.
Starting Statistics: 5. Eve's high speed is a good advantage to her, as it
makes her able to dodge well. However, her poor attack makes itself very
apparent very quickly, making dealing with rooms a chore. Her fairly low
health prevents her from getting valuable devil room upgrades, which
generally happen to be damage-related: thus Eve can be easily overwhelmed
or cornered despite her high speed.
Starting Items: 3 Eve's starting items both require Eve to take damage or
be at critical health levels: thus, they cannot be reliably used at all.
Eve's base offense and health make her unable to adequately capitalize on
her items, and her lack of consumable items also hurts her. In the event
that one gets Guppies' Paw, or a significant number of Soul Hearts, Whore
of Babylon can theoretically be made into a permanent upgrade, in which
event Eve will be statistically superior to the other characters. The odds
of this happening in any particular game are quite low, however.
Viability: 4. Eve simply cannot manage crowds, and if one is playing well,
her starting items will rarely take effect. Eve will need help in virtually
every category in order to make a serious full-game run, and can easily be
killed as early as level 4 given a cramped room with high-health enemies.
Playing with Eve will often be tedious and unrewarding.

6)	Samson
Samson is considered the "berserker" by some. His base attack is good, his
speed is average, and his shot speed is very quick. He also starts with
"Bloody Lust", a useful anti-boss and crowd-control passive item. However,
he starts with only 1 heart and 1 soul heart, putting his health on the low
end, and his firing rate is quite slow. Samson is a challenging character
to use that relies a little too much on lucky breaks to do really well.
Starting Statistics: 4. Samson's poor health and slow rate of fire makes
both attack and defense problematic for Samson. His damage per shot can get
very high with Bloody Lust, but it relies on large numbers of enemies to be
effective, and large numbers of enemies tend to get Samson killed due to
his poor health and rate of fire, making playing with him an embodiment of
"Catch 22". Given a rate of fire bonus (particular #1 or Sad Onion)
however, Samson can shred enemies with the best of them.
Starting Items: 4. Without Bloody Lust, Samson would be worthless. With it,
Samson is playable. Bloody Lust is a great item to have, particularly for
arena rooms, but ultimately pales compared to Judas' Book of Belial and
higher base attack, not to mention that against a handful of enemies, or
bosses that do not spawn cannon fodder, Samson loses his entire gimmick.
Viability: 4 Samson has only marginally more health than Judas, but
significantly less damage output. Samson runs will often end prematurely,
and like Eve, Samson play will often be tedious and unrewarding.

7)	XXX
The notorious XXX seems at first to bring nothing to the table: he can only
gain Soul Hearts (making damage effectively permanent), he starts with the
nigh-useless Poop, he has no consumable items to start, and his statistics
are strictly average otherwise. XXX play is tough, but the peculiarities of
his "soul hearts only" gimmick can actually give him opportunities other
characters cannot attain.
Starting Statistics: 4. Although XXX's lack of regular hearts is certainly
a liability, he starts with 3 soul hearts, meaning that the number of hits
he can take in a single room are actually comparable to characters like
Isaac and Magdalene. He also has no other statistical disadvantages; when
you play as XXX, you are playing as Isaac essentially. The harshness of his
health bar cannot be ignored of course, as every hit he takes is extremely
serious and cannot be healed. All items in the Devil Room cost XXX 3 soul
hearts, making such deals expensive and unlikely.
Starting Items: 1. XXX only has Poop. Poop has some uses: it can be used as
cover, it can be destroyed to perhaps reveal a coin...and that's about it.
Poop is useful in its own way, but without consumable items, XXX has by far
the worst item set up of any character.
Viability: 2. XXX can enter Arenas at any time, giving him unlimited access
to valuable Boss Arenas. XXX can ALWAYS use Whore of Babylon, and Guppy
makes a great gift to XXX because he will respawn with 3 soul hearts,
rather than 1 regular heart. Finally, although unconfirmed, finding Soul
Hearts seems to be relatively easier for XXX than for other characters; if
his health can be jealously guarded through Level 4, one can often find XXX
walking around with 10 or more Soul Hearts quite quickly. Many items are
useless to XXX however, such as Yum Heart and Guppies' Paw (though the Paw
is worth at least touching in case one can get the Guppy transformation),
and XXX cannot (reasonably) exploit the Arcade at all, since he cannot play
the Blood Bank without losing health permanently, a serious problem.
Despite everything, XXX play can be fun (more fun than Eve and Samson play
in my opinion), but it's still very difficult to carry XXX all the way to
the end, and more often than not, runs will end in failure with XXX more
often than with other characters.

Tip #7: Boss Strategies

These strategies will provide methods of fighting the bosses, and some
observations on their attack patterns and weaknesses. It will not provide
steps for each subtype or "champion" form of the bosses: fighting these are
not substantially different from fighting the regular versions in terms of

Levels 1-2

Monstro: While often cited as one of the more difficult bosses in the first
two levels due to his high health and high damage, Monstro is in fact the
most predictable of them all, and can be easily beaten without taking
damage. Monstro's slow hops do not cover much ground, and one can easily
stay ahead of him, even with Magdalene. His blood belch attack has two
weaknesses: it does not strike anywhere except in the fairly narrow cone in
front of him, and many of the blood balls can be destroyed by your tears.
When he readies his blood belch, he pauses and makes a face: simply move 90
degrees around the line of fire and this attack will never hit you.
Monstro's large leap attack always lands wherever you were at the moment he
launched: just run away, towards the most available space, and shoot at
where he will land to destroy any blood balls that might reach abnormally

Larry Jr.: This boss moves quickly and randomly, and you are often caught
in a rock maze when fighting it. However, its health is low, and its
movement being TOTALLY random, an agile and aware player can defeat it
without taking damage. Simply focus your fire on one of the worms, do not
let yourself be trapped by poop (keep 4 directions available to you at all
times), and if both worms seem to be closing in on you, flee to a safer
location, then resuming attacking your chump.

The Duke of Flies: The Duke will bounce of the walls at diagonal angles,
and never directly attack you. He will simply spawn a cloud of various
flies to protect himself, and occasionally send the flies in your
direction. His health is terrible: fire at him continuously and swat flies
if they get on your flanks or behind you. High rate of fire makes the Duke
laughably easy, but even Eve can take the Duke down without a scratch as
long as the player does not forget that the flies can hurt.

Gemini: Slower characters might have a little trouble with Gemini, but in
general, all one need do is move around the room and shoot. Do not let the
little fetus get a line of sight on you: the blood shot it spits moves
quite quickly. Once the large fetus is destroyed, the little one chases you
just as the big one did, and should be dealt with in the same way, keeping
in mind that the little one can fly over cover and is easily deflected by

Famine: When you stand to the left or right of Famine, it will almost
always charge: when you stand above or below it, it will almost always
spawn Pooters. If you have high damage stats, take the above-below stance
and destroy the Pooters quickly, or stay our of their attack range. If your
damage is lower, or you are simply confident, take the side approach, side-
stepping the charge then returning fire. You can keep Famine in a fairly
continuous charge loop until he turns into a head, at which point he fires
3 blood balls in a spread shot. In this phase, keep your distance and stay
light on your feet, dodging either between the blasts if you are a slower
character, or simply racing past the outlying shot if not. Do not double
back, lest you run into a shot you would otherwise have dodged.

Steven: Not substantially different from Gemini, except Little Steven is
not attached to an umbilical cord and is thus slightly more dangerous.

Widow: Probably the second hardest of the levels 1 and 2 bosses, Widow has
a fast and long-range hop, spawns spiders and egg sacks, and unleashes
sticky white fluid to trap you. The best strategy is to cut regular turns
while running, as her hop is faster than your run (unless your speed is
abnormally high), but not as maneuverable, making side-stepping the best
evasion option: she tends to jump every 3/4 of a second once she lands, so
change your direction about a half-second after she lands from her previous
jump and she will never quite hit you (it will be close however). Ideally,
bait Widow into jumping on her own egg sacks, as this will control the
number of additional enemies without distracting your attacks. Eliminate
spiders if they are near you, they move quickly and are more dangerous than
flies are. Stay out of the fluid at all costs.

Pin: Pin has only two attacks, and both are very easy to avoid. When the
fight starts, head to the east or west side of the room, at the wall, then
wait. Pin will lunge from out of the ground; dodge up or down, fire at Pin
as he sinks back into the ground, then return to exactly where you were.
Pin will come out again from roughly the same spot as before; dodge up or
down while firing, etc. On occasion, Pin will appear from the center of the
room and launch a green mortar ball at a random direction and range: just
keep your distance and keep still (unless the ball is clearly coming at
you), and the odds are very high the mortar will not land anywhere near

The Blighted Ovum: The blood trail the large fetus leaves behind looks
intimidating, but it actually cannot quite cover the floor entirely: simply
stay ahead of the large fetus like usual, taking care only to not go too
far ahead of it. The small fetus is detached but floats absently in the
middle of the room, often not participating in the battle at all. Not
substantially different from fighting Gemini or Steven.

Gurdy Jr.: Count yourself unlucky if you fight this little terror, because
Gurdy Jr. is far more difficult than Gurdy herself. She can spawn 2
pooters, fire an 8 directional spread of blood bullets, and most dangerous
of all, charge you at high-speed and start bouncing unpredictably around
the walls. It is vital to keep your distance, and stay as close to a 90
degree angle to her at all times when she is not charging. This is because,
thankfully, Gurdy Jr. follows the laws of physics, and so if she charges at
a 90 degree angle, she will only ricochet at a 90 degree angle, meaning she
will go straight back the way she came. Being near the north-south walls is
more dangerous, because she will bounce more and you will have less room to
maneuver: being in corners means almost certain pain. Stay in the open, and
give her everything you've got.

Levels 3-4

Chub: Chub will move around randomly, occasionally spawn chargers (up to
4), and charge at YOU in a rather intimidating manner. Circle around the
outside of the arena, destroying her spawn if it is near you, but otherwise
keep your fire on Chub, as she will often destroy her spawn for you. When
she charges, do not fire directly at her, as your tears can slightly alter
her trajectory up or down, causing your dodge to be ineffective; fire at
her sides and back instead. If you drop a bomb in her path while she is
charging, she will swallow it, pause, and then take a good bit of damage.

Fistula: Fistula is not terribly difficult, and if you have the
flight+spectral tears combo, will never hurt you: hover over a rock and
fire as you like.
Without this combo, fighting Fistula is simply a matter of discipline. Its
only attack is to accidently bump into you: its gimmick is that it splits
into more and more pieces. When it first splits in two, pick one half and
split it, then pick another half and split THAT one, then kill the
resulting charger: repeating this process will minimize the number of
Fistula pieces flying around. The pieces cannot pass over rocks, and are
fairly responsive to the knockback of your shots: use the rocks as cover
and as bases to ward errant pieces away, and move deliberately.

Gurdy: Gurdy is a pain. She cannot move, but spawns blood pustules and
pooters with alarming frequency, and fires a fairly hard to dodge 5 way
shot. There is a chance you will start this fight with cover in the form of
rocks on the south side of the room: if you do, simply hide behind the
rocks and her blood shot will never hit you. If you have poop, deploy it in
a convenient spot and use it in the same way as you would a rock, being
careful not to hit the poop with your tears lest you destroy it. When Gurdy
spawns pustules, eliminate them immediately; when she spawns pooters,
ignore them until they come into attack range, then destroy them. If you do
not have cover, use the following strategy: move to the east or west wall,
about 3-4 steps from the south wall. Fire at Gurdy as normal. When her head
goes into her body, she is about to fire: move to the south wall and run
along it to the other side of the arena. Repeat this movement pattern,
moving back and forth, and her shots will likely never strike you.

Peep: This disgusting little blob of lard will quickly teach you the
meaning of contempt. Peep is annoying and gross. He has several attacks at
his disposal:
1)	Peep shudders and pees all over the ground in a puddle centered on him.
Simply stay away from him, and the pee, and it will vanish after a few
2)	Peep smiles and takes a little hop straight up, spraying pee balls in
six directions. Keep your distance and stand just a few degrees off the
90, you should dodge the attack easily.
3)	Peep smiles, raises his flappy little hands (almost like he's saying,
"SURPRISE!), then leaps up and smashes down where you are standing. Upon
landing, he fires pee balls in 8 directions. When you see him raise his
hands, start running as far away from your present position as you can,
then dodge between the balls.
4)	When he is down to 66% health, one of Peep's eyes pop out and start
bouncing around the room at diagonals, floating over rocks. At 33%, Peep
loses his other eye, as well.
Peep is irritating, but if you catch on to the pattern of his pee ball
shots, he can be fairly easily dodged. His eyes are indestructible however,
and move quickly; always keep aware of the entire room when fighting Peep,
never holding completely still and always keeping as much distance between
yourself and Peep as possible.

Pestilence: Pestilence floats idly around the room, firing green mortar
balls randomly (but typically not very far) and spawning chargers and
spitters (up to 4 enemies total). Unless they are a clear threat to you,
let Pestilence destroy his own minions for you with his mortar shells, and
avoid stepping in the green sludge he and his shells leave behind. When
you've depleted about 2/3rds of his health, Pestilence will spawn attack
flies instead of chargers and spitters: the fight essentially gets easier.
Keep attacking, keep your distance, and you will prevail.

The Carrion Queen: an upgraded form of Chub, the Carrion Queen can only be
damaged in its soft pink tail segment. It will charge you, exactly like
Chub, and will eat bombs left in its path when doing so, dealing damage to
the boss. Aside from its weak point that must be targeted, the Carrion
Queen also differs from Chub substantially in two ways:
1)	Rather than spawn chargers, Carrion Queen spawns red piles of poop. This
poop injures you like fire, does not leave behind pick ups if destroyed,
and respawns as a full pile of red poop after a few seconds if
destroyed. Do not touch the poop, and avoid even destroying it: the poop
has a tendency to respawn on you if you cross over where the poop once
was. Leave the poop standing and simply avoid it like spikes to prevent
this from occurring. Carrion Queen only seems to lay up to 5 red poops.
2)	Once about 2/3 of her health has been drained, Carrion Queen stops
charging or pooping and bounces around the room in a series of
diagonals. In this state, its trajectory will change based on obstacles
(rocks, poop, etc.) The fight will be much easier from here: avoid the
poop and the Queen, firing at her tail, and victory is assured.

The Husk: an upgraded form of The Duke of Flies, the Husk is nominally more
difficult but ultimately is as threatening as its former self. The Husk,
unlike the Duke, can attack by launching blood bullets in 8 directions, and
can cough up spiders in addition to a fly veil like the Duke's. Kill the
spiders as soon as they show up, and keep a half-screen's distance so you
can avoid the blood bullet attack. Otherwise, treat Husk as the Duke: high
RoF or penetrating attacks will kill it quickly.

The Hollow: this "upgrade" of Larry Jr. is actually substantially easier
than its former (also easy) self. The Hollow, like Larry Jr. is two snakes,
but these snakes fly, and move on a diagonal pattern. The snakes simply
bounce around the room based on physics. Stand in the north part of the
room, focus on dodging the snakes by moving left and right, and fire at
whichever snake is the most exposed at any given time. Victory will come
quickly and painlessly.

The Wretched: an upgraded form of Widow, the Wretched is substantially
harder than its former self (which was already relatively challenging). The
Wretched spawns two spiders at a time, and these spiders can be more
advanced enemies as well, quickly filling the room with quick and erratic-
moving enemies. Worse, the Wretched lays down a much larger puddle of white
fluid, filling a large part of the floor, and when it does so, fires white
bullets in eight directions. The Wretched also constantly hops toward you.
As is typical of radial-firing bosses, keep your distance as much as is
possible to move between the shots, and use the dodging strategy of the
Widow. Destroy the Wretched's spawn immediately, and again try to trick
Wretched into crushing her spawn whenever possible. Stay flexible, ready to
kill spawn when needed, dodge at all times, and fire at the boss when given

Levels 5-6

Monstro II: an upgraded form of Monstro, Monstro II moves somewhat faster
and has more health than Monstro. Most importantly, Monstro II's attacks
are harder to dodge, and require a somewhat different strategy:
1)	After his off-screen leap, when Monstro II hits the ground, he fires
blood bullets in 8 directions, rather than random splashes of blood.
Keep your distance and dodge between the projectiles, as these cannot be
shot out of the air like Monstro's blood splashes can. He will then
launch again, this time spawning red-bottomed flies that burst into
blood bullets when killed. His blood beam destroys these for you, as
does his giant leap attack. They also move fairly slowly, and should be
ignored unless necessary.

2)	Monstro II fires a blood beam rather than puke blood splash. Shortly
before firing, Monstro makes a face. Continually circle Monstro II to
avoid this attack, and bear in mind that Monstro does not fire the beam
when you are standing directly over him: only below or to either side.
Otherwise, deal with Monstro II just as Monstro.

Loki: Loki focuses on radial blood bullet attacks and spawning fat red or
black Boomflies to clutter up the arena. During the fight a slowly moving
spike trap roves around as well, providing cover to Loki and interfering
with your movements. Despite all this, Loki is fairly easy to defeat
because he telegraphs his attacks.
1)	When Loki takes on a "concentrating" face, he will spawn a boomfly. Kill
the fly immediately: if it is a black one, kill it near Loki for some
bonus damage.
2)	When Loki takes on a "surprised" face, he will fire in 8 directions. As
always, keep your distance to dodge properly.
3)	When Loki raises his hands to his mouth with glee, he will teleport. He
will not try to hit you, and so this is a non-threatening move.
4)	When Loki keeps his normal expression and raises his arms slightly, he
will fire bullets in the cardinal directions, then in the four
diagonals, then the cardinal directions again (graphically, + X +). Move
minimally to avoid the bullets and return fire.
By observing Loki's tells, his attacks can be easily countered. Keep up the
offense and he will go down obligingly.

War: the third Horseman is substantially more aggressive than the previous
two, as befitting his title. War's primary mode of attack is a screen-
spanning charge. He will charge at you from right to left, then appear
lower down the arena for another pass, then appear again nearer the top of
the arena, then finally finish his charge by moving to approximately the
point from which he started. After charging, he will often fire an 8
direction blood bullet burst without warning, and will sometimes do so
randomly while floating around idly.
The other major attack War performs is when he holds his horse over his
head, growls, and leaps up offscreen. Six troll bombs will spawn randomly
in the room while he is gone: watch the bombs carefully and note which
appeared first. From this bomb, judge the positional relationships of the
other bombs, and quickly move to a part of the room far from the blast
radius, keeping in mind that the explosions will move the bombs around. If
you know which bomb appeared first, you can get an idea of whether the next
bomb will be moved, and if that bomb's explosion will move the next, etc.
Chaos theory will sometimes thwart you with a haphazard pattern or an
undodgable one: count yourself unlucky if this happens.
Once War has lost about half his health, he dismounts his horse and simply
runs after you like Gemini. Run away around the room and fire back at him
constantly: there is nothing else you can or need to do to win from this

Gish: "something sticky" is no more difficult than a Monstro. He fires a
black mortar shell instead of blood, which is easily dodged by running from
the vicinity of the blast radius, and the mortar leaves behind sticky (but
not directly harmful) black ooze. Gish has a giant leap, but on the first
leap, will spawn nothing: on the second leap, Gish spawns smaller Gish from
himself, but since these only fire diagonally, they are easily killed or
ignored by standing to the side or above/below them. Hammer at him until he
goes down, dodging his simple attacks.

The Bloat: In this author's opinion, Bloat is the most difficult boss in
the game next to Satan. A variation of Peep, he oozes large amount of
harmful blood, jumps around, fires radial blood bursts, and starts with
both eyes already popped out. Most dangerous of all, whenever you stand to
the side of in front of The Bloat, he INSTANTLY fires a blood beam at you.
What can we do?
Stand ONLY behind the Bloat: never move to any other vulnerable side. Dodge
the eyes and keep your distance as best you can to avoid the blood ooze. If
you find yourself no longer above Bloat, wait it out near the bottom of the
screen until he leaps again, allowing you to regain his back. If you happen
to have a magician card, or even a familiar that can fire with you, this
fight will be much easier for you, as you will be able to attack the Bloat
from an angle without worrying about the blood beams. Mom's Knife can be
fired at an angle, which makes it an absolute godsend as well.

Mask of Infamy: Possibly the most irritating boss to defeat, Mask of Infamy
has no health bar. It has two bodies, a mask and a heart. The heart will
simply run away, while the Mask tries to charge at you. First, attack the
heart; the mask is invulnerable until the heart is dead. Once the heart is
gone, the Mask speeds up, but now is vulnerable from the back just like a
Knight. Goad the Mask into charging you, then move behind it and fire
(easier said than done since the Mask moves VERY quickly). You may find
dropping bombs increases your chances of damaging the Mask, but regardless,
expect to take some damage and do a fair amount of swearing, as the Mask
likes to abruptly change direction and smack into you without fair warning.
Anything that can slow the Mask down will make the fight MUCH less

Mom: the first of the "set bosses", Mom always appears in Depths/Necropolis
2. The room is covered with debris, and four portals are located where
doors would be in other rooms. From these spots, parts of Mom will poke out
and do various things.
At the start of the battle, run straight to the center of the room if there
are any rocks there at all. Mom's foot will come to crush you: move away
and let the foot smash these rocks in the center. If any rocks in the
direct center are left, and you have extra bombs, blow them up: keeping the
center of the room clear is the most vital step to surviving this fight.
Mom can attack in the following ways:
1)	Mom tries to stomp you with her foot. This attack is preceded by an
"urah!" grunt from Mom, and a rapidly shrinking shadow over Isaac. It
takes about 1 second for the foot to strike, from first shadow
indication and grunt to touch-down; the foot locks onto your movements
until just before the foot actually strikes. Dodge down, left or right;
if you dodge up, the foot's hitbox is slightly harder to avoid and may
hit you even though the foot did not.
2)	If you stray too close to the portals in the walls, Mom may swat you
with her hand; it has a wide hitbox and is therefore difficult to dodge.
It is because of this attack that clearing the center is so vital: the
center is the only part of the room entirely safe from this attack.
3)	What appears to be Mom's buttocks pops out and spawns a random enemy.
None of the enemies are very difficult to defeat, and are often crushed
by Mom's foot if the foot is kept in the center of the room. Only attack
enemies that either charge directly at you or can fire bullets in your
direction; leave other enemies (like Mulligans, the swollen cry-baby
enemies) to wander around the periphery where they do no harm.
4)	Mom's eye pops out. The eye will not really attack you, but its
appearance usually preceeds a transformation into a buttock or a foot-
stomp. It is otherwise merely a vulnerable place to strike Mom.

Attack ANY exposed part of Mom to hurt her. If you are daring, you can try to
get Mom to stomp on a part of herself coming out of the portals: this deals
her an enormous amount of damage, often killing her outright. Using the Bible
during this fight will score you an automatic victory.

Stay calm at all times, and keep on the move but in the center as much as
possible. If you eliminate the most threatening enemies, and simply focus on
dodging Mom's foot, then Mom will go down surprisingly easily.

On occasion, Mom's death causes as explosion that can harm you. It seems to
occur randomly, and can only be thought of as very bad luck. Once Mom is dead
, you cannot leave the arena through the doors; keep this in mind on
depths/necropolis 2 when collecting items, considering the use of blood banks,

Levels 7-8

Lokii: Loki is back, split in half and ready to be as simple to defeat as
before. Lokii has no moving spike trap to help it this time, and its attacks
are identical to its previous, whole form. Lokii is merely two Lokis with half
health each: focus on one, bring it down, then eliminate the other one,
keeping aware of their facial expressions to dodge their attacks.

Blastocyst: A very rare fight, the Blastocyst is a cousin of Fistula in that
it breaks apart into smaller and smaller pieces. In its first, large form,
Blastocyst tries to bump into you and fires 8 way radial bursts when it grins.
Once split, the two smaller versions can fire either + ways or X ways, and
still try to bump into you. These again split into 2, creating up to four
small Blostocysts that try to bump into you and fire only in + formation.
Finally, these are reduced to a hopping little larva-thing that has no attacks
anymore; they are effectively neutralized at this point, simply avoid
accidentally running into them. Blastocyst is a simple boss, but can be
challenging without speed boosts, flight, or at least pretty flies or other
shield-type items.

Scolex: Fundamentally, Scolex is the same as Pin. Use the same strategy to
defeat it, noting only that when it pokes itself out to fire mortars, it will
launch 3 instead of only 1. Additionally, Scolex is only vulnerable in its
tail: watch where it goes to sink under the arena and fire at the exit point
to strike it weak point.

Daddy Long Legs/Triachnid: essentially the same boss, this spider-like foe
will try to crush you with its attacks. It cannot be damaged when it hugs the
ceiling; attack when it lets its body hang low. Most of the time, it will only
try to stomp you with its feet; sometimes it will stomp randomly, sometimes it
will home in on you like Mom (but stomping multiple times in a row). No matter
the variation, watch the shadows and dodge quickly. The feet have very small
hit boxes and so are not hard to avoid. Occasionally, the boss will cough up
some spiders: eliminate them. Finally, the boss might bring its head up, then
smash it down, firing an eight-directional blood burst, prompting you to
engage blood-burst dodge routines.

Death: The most difficult of the normal Harbringers to defeat, Death has a
variety of powerful attacks it will use to exterminate you.

-It will summon two to four small spinning scythes to attack you. If two, the
scythes will home in on you and follow you for a while; if four, the scythes
will converge on your position, then sail off screen. The scythes can be
destroyed with your tears: keep moving and destroy the homing scythes, or in
the case of the quad scythes, destroy one to make a gap and run in a diagonal
toward that direction.

-It will pull out an hour glass, causing you to slow down. This makes dodging
far more difficult, so simply do your best and shoot down as many scythes as
you can while still trying to dodge.

-It will spawn two Knights to wander around the room. Attack them when you
have an opportunity, but otherwise keep your fire focused on Death and simply
try to avoid them; they take too long to destroy without bombs or piercing

Once Death has lost about 1/2 its health, it will dismount and send its horse
flying through the screen, repeating the same pattern War's charge takes
without pause. Death itself will simply float around the room, continuing to
harass you with its attacks (tending to spawn Knights more often). The horse
can kill Knights for you, so memorize its pattern (its quite easy) and
continue beating down Death. Once it is gone, eliminate the horse.

Mom's Heart/It Lives: The second "set" boss, Mom's Heart/It Lives always
appears as the boss of level 8. The two versions are not much different: the
boss sits in the middle of the room, like Gurdy, summoning monsters (It Lives
can also summon Monstro, Larry Jr. or Chub). As long as there are monsters in
the arena, the boss retreats somewhere in the ceiling and cannot be harmed:
eliminate the monsters to bring the heart down again, allowing you to harm it
for a while. Because of the phase nature of this boss, it is actually easier
than Mom to fight (easier than many bosses, in fact). Mom's Heart/It Lives
will never summon multiple waves of enemies, so fighting it is simply a trial
of endurance. At about 1/3 health, the boss no longer retreats and starts
randomly firing mortars. During this phase, stand on one side of it (right or
left as you prefer) and continue firing, moving as little as possible to dodge
the rare mortar that threatens you and eliminating what few monsters survive
the random mortar attacks. After a time, you will prevail, quite possibly
without even being harmed.
If you have the Bible, use it for a 1-shot victory!

Floor 9: Heaven or Hell?

If Hell (Sheol): Satan. Satan is truly the King of Hell, a monstrously
powerful enemy with three full health bars to be depleted before finally going
The fight begins with Satan summoning The Fallen (see below) and two exploding
leeches. A good way to start this is to lay a bomb down in front of Satan
about three seconds after you enter the room: the Fallen and the leeches will
spawn just before the bomb explodes, destroying the leeches and dealing a good
amount of damage to the Fallen. Fight the Fallen as normal (see below),
keeping in mind that Satan acts as both cover and an obstacle during the
Once the Fallen is destroyed, Satan reveals his true form and begins to
attack. At nearly all times, Satan fires a 5 point spread shot at you,
followed by a 4 point spread shot, continuously. Stand to a side (the one that
gives you the most space), hug the wall, and dodge in-between the bullets,
moving to dodge the middle shot of the 5 point spread, then returning to your
previous spot to dodge the 4 point shot. Do not stop firing: if you have short
range or poor speed, you may not be able to survive.
If you pass in front of Satan, he will fire a blood beam from either his mouth
or from both hands. If Satan's eyes shut, then he will fire from his hands:
stay directly in front of Satan to avoid this attack If Satan's eyes stay
open, then he will fire from his mouth: dodge left or right to avoid the beam.
After depleting Satan's health bar, he will ascend to the ceiling and begin
trying to stop on you, as Mom's foot would, while spawning exploding leeches.
Satan stomps with two feet, one after the other, at a quicker pace than Mom's
foot, and they are the only vulnerable part of Satan in this form. The leeches
will always respawn, but there will never be more than 2 at a time. Avoid
destroying the leeches and simply dodge them: it is very difficult to see
where the leeches spawn while Satans feet are stomping you, and so by
destroying leeches, you actually make it much more likely that you will
accidentally bump into one. Dodge the feet by running around the outside of
the arena, avoiding the leeches continually, and fire at the feet. Eventually,
Satan will perish, but not before you've taken a beating: my record is
defeating him while taking only 7 hits.
Do NOT use the Bible on Satan: it will instantly kill YOU.

If Heaven: Isaac! Having a few pretty flies, a guardian angel, or other
shield-type familiars will make Isaac much easier. Isaac has three forms:

-Form 1, Fetal Isaac: Isaac lays in the fetal position, occasionally firing
radial tear bursts (12 directions) and retaliating with tears when hit. The
tears can be knocked out of the air, much like Monstro's blood barf, but come
fast and hard. If you do not have sufficient shield familiars to block the
shots, keep moving and fire in bursts: many more tears seem to be fired the
longer you hit Isaac.

Form 2, Standing Isaac: Begins at roughly 3/4 health, only change here is that
Isaac now fires 4 purple homing tears instead of omni-directional regular
ones. He will still retaliate when hit, and should be dealt with exactly as
Form 1.

Form 3, Ascendant Isaac: Isaac sprouts wings, and smiles through his tears, at
1/4 health. This is when it hits the fan: Isaac will now fire homing tears in 6
directions (very hard to dodge), fires random pillars of light at all times,
and summons swarms of angel babies, which fire 3 point tear shots while
screaming and floating toward you. I have seen as many as six angel babies
spawned; this part of the fight is extremely dangerous. Destroy any Angel
Babies that get near you, and concentrate your fire on Isaac (he will no
longer retaliate). Dodging is now nearly pointless due to the crowding on-
screen and the random light pillars; without shield familiars to absorb shots,
this phase will likely kill you. If you are without protection, just fire at
Isaac and try to kill him first!
Do NOT use the Bible on Isaac: doing so will instantly kill YOU.

If you beat Isaac, and are holding the Polaroid trinket, you get to go to one
last stage; the Chest.
The Chest: vs. XXX

XXX is basically the same as Isaac, following the same phase structure. XXX
also spawns flies when hit however (bet you're glad you have skatole now!),
and fires even more homing tears. Do not let up on him, and hope the four
items you got at the start are enough to win this battle. If you paid
attention to strategy and got a few good items during the game, it is likely
that you made it to the Chest because you are equipped enough to be able to
defeat this super boss: use what you have, and good luck. Do NOT use the bible
on XXX: doing so will kill you.

Bosses that may appear anywhere:

The Fallen: This devil is a tricky foe to face. Its primary attack is firing 5
point, then 4 point, blood shots at you. If you are confident, dodge between
the shots; if not so much, continually circle the boss and try to outrun the
spread of the shots, or combine both tactics. Sometimes, the Fallen will chase
you like Gemini: flee and fire back. When the Fallen stops chasing, it will
fire a + formation of blood beams: move to an angle with the Fallen to dodge
the attack. At 1/2 health, the Fallen will split into two. The little Fallens
attack the same as the larger version, although they do not cooperate very
well, to your benefit. Pick one to focus fire on, and run constantly, to

Headless Horseman: Headless Horseman is a floating head and a horse. The horse
charges from right to left like War's charge, only continuously. The head
fires 3 point blood shots (easily dodged), coughs up blood mortars shells
vaguely in your direction, and occasionally also charges around like its
horse. Eliminate the head first, as it has a greater variety of attacks (and
the blood mortars leave behind harmful ichor on the floor), then deal with the
horse at your leisure.

Conquest: the neglected horseman of the apocalypse that was supposed to stand
in Pestilence's place, conquest is a formidable foe. It has three attacks:

-It fires a + formation of homing tears, which move very quickly. Dodge them
as well as you can.

-It raises into the sky, much like War, and rains down pillars of light
randomly. Just stand still for this attack: the odds of a beam appearing where
you are standing is quite slim, versus if you run around madly, in which case
you increase your odds dramatically.

-It charges off screen. Something like 9 Conquests will charge from the right,
all over the screen. Dodge between them, firing as you do so: every one of
them can be damaged.

Continue avoiding its attacks and firing away to secure victory.

Sometimes in the Devil Room:

You fight Krampus. Basically the same as the Fallen, but with two key
differences: it does not charge you, and it does not split in half. It still
fires the + direction blood beams, but there is little warning when it does
so: it will make a noise and change its expression, but it leaves you barely 1/2
a second to get out of the way.

Miscellaneous Advice:

-Ipecac, Epic Fetus, and Dr. Fetus are very dangerous upgrades: carefully
consider what kind of build you have, and how present-minded you are in
general, before picking these up. If you have My Reflection or Three Dollar
Bill, do not get Ipecac or Dr. Fetus.

-The Bean is easily the worst item in the game, worse even than Poop (which at
least has some interesting uses). Yet even it can be helpful.

-Holy Water is a close second for bad items (not that it matters: without the
D6 you may as well pick it up), as is We Need to Go Deeper (except on floor 8,
if you KNOW you want to go to Sheol)

-Lemon Mishap is hard to use, but can be very effective on Larry Jr. or other
randomly roving enemies.

-Mom's knife can be fired at angles (hold two arrow keys at once) and can be
used as a melee weapon.

-If you spot a Boss Arena, it is often worth your while to drop to 1 heart to
get inside. Make sure you can heal when you beat the arena, and do not lose
soul hearts to gain access (a blood donation machine is a wonderful boon if
you have lots of soul hearts)

-If you blow up beggers and devil beggers, you increase your odds of finding
the Devil Room after beating the boss.

-Avoid using Teleport! Pills until you have cleared the floor, on the off
chance (approx. 5%) you find the I AM ERROR room and have to skip boss or item
room items.

-Pills are scary to use; however, the benefits of good pills outweigh the
drawbacks of bad ones, and so should always be eaten to find out what they do
(AFTER clearing the floor, in case of teleport! Pill).

-If you collect any 3 Guppy items during a run (just having possessed them for
even a moment is enough), you will turn into Guppy and have permanent flight,
as well as the "mulligan" ability (your tears cause attack flies to spawn and
further damage your enemies).

-All the trinkets are useful, except the Cursed Skull. Never, ever pick up the
Cursed Skull, it's odds of actually helping you are nearly 0.

-Liberty Cap, any of the Coins (especially bloody penny), and Cancer are among
the best trinkets.

-However, if you pick up Cancer while you have an eternal heart already in
your inventory, it will be destroyed.

-Auto-healing items, like Charm of the Vampire or the Tick trinket, are
anathema to you if you are using Whore of Babylon continually: don't use them!

-XXX with the Polaroid is nearly unkillable in a single room.

-If you see spike tiles arranged at 45 degree angles to one-another, you can
walk between them and take no damage if you are precise.

-You can sneak into locked rooms via the Secret Room if you have enough bombs,
and the Secret Room is in the right spot.

-If you skip Devil Rooms (are given the option to enter and opt out), you make
future God Rooms more likely.

-If you have never picked up an item before, pick it up, even if only for a
moment, to boost your collection status.

-You can only have up to 12 regular hearts, but unlimited Soul Hearts.


-To Edmund Mcmullen and his team, for creating BoI and filling many happy,
disturbing hours.

-To the BoI wiki for its community's assistance and dedication

This unauthorized guide copyright 2012 by Three Fates Games LLC

Written by: Samuel Boyer (Atropos)

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