I finished watching this anime yesterday at 2 AM and when I did until 2:30 AM I just stared at the screen trying to assimilate the last 5 episodes. I was like: OMGx2 or something.
Now the review its self.
Story: 9/10
The way how the story evolves is really cool. Some might call it slow but I think that this is the way an semi-horror anime should indeed evolve. Because of the few details that the story gives it rely makes a chill run down you're spine and u fell like u sneaked you're nose where u should not. But in the end what really matters is on who's side you are at the very end (and neutrality is not allowed, believe me).
Art:9/10
All the special effects are wonder full made. The way the characters are drawn is also quite good, especially strange / horror scenes. Also the landscapes are realistic.
Sound: 7/10
I didn't particularly listened to the songs so I shouldn't comment here but I DID liked the 2nd opening:"Calendula Requiem" by kanon x kanon (eps 12-22).
Character: 9/10
Although there were some super twisted and some times crazy characters (semi-horror anime so I think it's understandable ) there were also some very good ones. Most of theme were something between and their personalities were very close to the real human ones. And what they done shows us what COULD happen IF we would let the fear and the thirst for revenge to lead us.
Enjoyment: 8/10
Well here it depends how u define "enjoyment". It's that chill that makes you're stomach go to you're throat? Or its pure happiness. I don't know how to define MY enjoyment bu I know when I feel it and when I watched this show I definitely felt a blast in some moments and I wanted to curse some times.
Overall: 9/10
Its a very good anime and if u like supernatural stuff u should definitely watch it.