Ok, I will start my review appointing to the problems that I think that make some people hate this horror and suspense anime. - The confusing plot (if you don't pay attention) - script holes (It's very difficult work with this theme without some hole in the script to help the trama)
Is a fact that something are strange at our point of view in the anime, for example: If Misaki knows the whole time about the extra student, why her didn't something with her doll eyes or something like that? Why everyone do suspense and don't tell anything to Sakakibara until Izumi came to the school next day? Why the end was so chaotic, what is this plot?
Well, I will try to explain why I like so much this horror/suspense anime and tell my vision about these points.
Calamity
All the plot spin trough a curse that starts 26 years ago in the class 3 - 3 of the Yomiyama North Middle School. Every year this curse starts for some reason, killing the students in this class and your relatives, now, the objective of the students is stop the calamity that starts when Sakakibara came to YM (Yomiyama North).
I don't know in the first time I watched, but this came to be my favorite anime, in any category, I really appreciate this show because he takes everything that is necessary to do a good story and a good plot;
- Nice characters, everyone in the right place, with the right time to be in the scene doing what he need to do, connected with the plot and connected whit us, viewers. - Red herrings. What a lot of people don't understand is that to make a good plot, a good suspense, you need a slower rhythm, and Another do this like a masterpiece. Another don't need to lie to you to make a good plot, they point a real doubt, a real question in your mind, and, after this, they broke this and came another doubt different, but keeping in mind what was telling before, they don't need to deceive you to seem good or intelligent, the plot is good exactly why you are discovering the clues with the characters, you are never in front of them, and never behind them. - A good soundtrack, it's simple but is very functional, the sound effects are very good to and the soundtrack is always scary, but something bring some piece in this "scary" and when it need, just put you without breath. The high tones that go increasing and increasing like a machine in a corridor or something like that, make you intentionally feels uncomfortable and it's bring some paralyzing experience - A good plot, all the investigation are fun to watch and make her purpose, the show never wants to be more than he is, just a good suspense anime ant that's it, don't need to be a masterpiece to be good, to bee captivating.
How the gore works (and works well)
One thing that works very well in this show it's the gore, not because is explicit and have a much of blood or something like that, it's because the anime prepare a solid ground to put this gore, slowly showing the mistery, slowly showing the school, the locations and a sequence of images that premeditate where this deaths will happen, so, when finally the calamity starts, the shock of the gore hits you in the face and you think --"what I'm watched right now??"-- and after this, the show starts to take a rhythm more and more aggressive, loud songs, loud musics and the mistery about to be solved at any minute. And then, we finally reach the last two episodes, when everything hatch in a madness and crazy massacre.
"Send the extra student to the afterlife"
This make any sense? this madness end? this whole plot? Well, to me, yes, much sense.
Think, if you have 15 years and see your friend down the stairs with a umbrella trough the throat, or your teacher putting a knife in his own throat too, after that, your parents, brother, everyone starts to die, and all the explication about all of this is a curse started years and years ago. This curse make everyone crazy, and the anime shows very well their decay and degradation, the protagonist starts to have strengths nightmares about seeing his own like the "dead student" and thinks that everyone is his fault. So this end can't be better, everyone in a sanctuary, so symbolic, but, when they discover that one person in specific is the "extra", they gotta madness to kill this person because this will stop the calamity, resulting in a massacre and a crazy end, but, functional. Everyone lost something, everyone just wants to stop this madness. The plot about the "extra" is very good, I really don't expected that, and the anime shows some clues about it, but I didn't believe it could be that. Well, a really and satisfying story and plot. Watch Another (or read).