I dropped the anime in middle of the 8th episode, so this is a partial review.
Pros: Interesting idea.
Meh: Graphics, Music
Cons:
Inconsistency
Reactions are not realistic
Character background is sappy
Character progression is ridiculous
Basic questions are not asked or answered
The story is about kids who got into something without realizing what it was. When they begin to realize, for the most part, the story demands that they do not react normally or that they wait before they do. Cause/effect reactions are inconsistent and happen at a time convenient to the plot. Further, the amount of time things take to happen are tied to the sub-plot instead of "reality".
The drawing is not that great; most of the characters look ugly. The music is nothing of note. The only thing that kept me watching was waiting for a big reveal or at least answer some basic questions. By the sixth episode i was getting bored, by the eight, i dropped it. What a waste of time.
The idea is interesting though. Just poor execution.