Story: The story is rather interesting, not quite what we'd expect, although when we are bought to the first part of the anime, we're not quite sure what to think of this, we eventually find out the protagonist's history, what happened to him and everything. We learn that they are trying to defeat an 'angel' but later find out that she is really just an human whom was able to program herself to acquire different skill and attributes leading to a war between the girl herself and people whom defy the school rules. The characters are dead and are having an afterlife in this world due to them in their previous world of not obtaining the childhood they should have received. Hence all characters are unable to die no mater the slaughter. However they become 'obliterated' when they fulfill 'all' their wishes and pass on to another world.
Animation: The animation is just as we'd expect from modern animation productions, good.
Sound: The sound, matching with the animation is decent, not much error in the process of doing the recordings.
Characters: The characters are very nicely panned out, with all the emotions and everything. The low part of characters is very very bad in fact. The characters don't seem to match the time of events in this anime. Everything happens quickly. It seems the protagonist and the leader of the defiant group seem to get along rather well, in fact in some audiences point of view at that stage of this anime, the two seemed to have an high chance of becoming an couple or something, yet the protagonist ends up with 'angel' after a short period of being with her. Also the new/replacement singer of the School band 'ends up' with an male character named Hinata. The singer becomes obliterated when Hinata tells her he would marry her, he final wish is fulfilled and she passes on the the next world, however after she is gone, it seems Hinata and the defiant group's leader then get along so well it starts hinting to the audience that there is a chance of them becoming an couple -_-
Overall: Overall the anime was excellent, with many different emotions incorporated into it. The anime contains action, drama, comedy, fantasy. The anime is funny and full of action at the start, but on the brink of ending, the last episode, is so very sad that it bought tears to many audiences. Although when Hinata claims he would've married the singer, many audiences cried of joy. The final episode's tears, however were not joy, but a bit of anger, pity and despair.
EXTRA!!!: In my personal opinion, the anime was fine, but the problem of the animes switching 'potential love partners' could be the result due to the anime being so short.
Thanks for reading :D Hopefully the review wasn't too bad :D