This is one anime that felt like it could be really good, but when I got through it I just both somewhat annoyed and disappointed. I'm someone who can take watching gore if the gore has a purpose, but I feel this anime existed for the purpose of gore.
**** I wrote this to try to avoid any spoilers ********
The story starts off with an interesting, but at the same time not unheard of premise. The students in this class don't seem to notice a girl in the class and from there the reason for this is explained. The problem
is though after the initial explanation followed by the events that occur as a result of this, the story gets to be very linear and not that well fleshed out. There's very little actual mystery going on.
Even the "plot twist" at the end wasn't something you couldn't see coming. I guessed wrong on the exact specifics, but I guessed correctly what kind of twist would be there. And even if you didn't guess that something like that would happen, the twist is so weak that you go "Eh, it's not that much of a twist". By about episode 6 it's less of a mystery and more of just pointless gore. And what little mystery they do have they drag the living hell out of. They could have condensed this down into a fewer number of episodes and the story would have been ok, but over the course of 12 episodes I was almost yelling at the screen "GET ON WITH IT!" because of how stretched out the plot is. Even the climax dragged out over 2 episodes.
The problem is they try to go too much for the shock value once the cause of the mystery is shown, but shock value doesn't hold your interest!! You can only shock people so many times before they become numb to it!!!!
Probably the best part of the anime. The art is really well done and sets the atmosphere, but the problem here is similar to the problem with the story. Once you've seen it in the first few episodes it doesn't change and you just sorta tune it out. The art can not hold your attention alone! It's actually one of my common beefs with so many anime's and such is people put too much emphasis on the animation and such. Art is wonderful, but 12 or more 20 minute episodes of wonderful art doesn't keep people interested.
I can make steak dinner look ascetically pleasing, but if the steak tastes horrible all that eye candy doesn't matter. It's the same deal with animation. Without the "taste" the art is just wasted.
Is it the worst anime ever? No, but it was one I was disappointed with. Not because I went in with high expectations, but because I was hoping it would at least give me something by the end and it really failed to do that. They put too much emphasis on generic blood and gore horror cliches and not enough on the parts that actually make for a good series. The one saving grace is that it is only 12 episodes so you don't need a huge time commitment to watch it.
There just wasn't enough material to keep the story interesting.
If you like gore fests you will like this one or if you need something to pass the time it is ok to watch since it doesn't require a massive time investment.
If you are looking for a good mystery or something with a little more punch go watch the Hikurashi series. Hikurashi has a plot and story telling style that is actually interesting and they use their "shock value" sparingly so that you don't get fatigued by it. That's a series you can watch even if you aren't a major fan of the horror/psychological/etc genre because of how well put together it is.