Yeah, I agree with your assessment. A fair number of horror manga (and anime) made their way to Indonesia and Nube is one of those and quite popular at the time. Unfortunately we got some chapters cut due to the ecchi content.
Since it's targeted for young/teenage boys (serialized in Shonen Jump), I guess that's why it can't be too scary. But when it's effective it's really pretty good. One of my favorite later chapters was the one with the ghost that insta-kills anyone who sees its face so they have to walk blindly. I also like the more Twilight Zone-y chapters like the one where Kyoko wakes up in a possible bad(-ish) future.
I'm surprised it got a recent sequel but nobody translated that yet...
Into the woods, but mind the past... Into the woods, but mind the future!