As I was watching though, the series grew on me and I found it quite entertaining and interesting and I'll explain why.
Story: 7
As I said I wasn't a fan of the senario when I began watching the series. At first I was impressed only by the art and that's what kept me watching. Yes, it doesn't sound very deep, but a long time passed since I'd seen such wonderfull art in an anime. After the first few episodes though, I was engrossed in the story. It wasn't at all what I was expecting. The story was much about one species - humans - trying to understand aliens and vice versa and that was done through the everyday life of a highschooler who was 'infected' with one of these parasites (luckily not in the brain). Of course there were killings and blood and slaughter, but just as much as it was necessary to give suspense to the story - most of the deaths were given much credit, it was not just gore.
What I found remarkable about the story was its pacing. We all have watched an anime which is awfully dull and in the last few episodes there is a thunderous bang! that tries to make up for all your lost time, everyone gets killed or everything is explained. That's not what happened here. The story unraveled smoothly and every episode was equally interesting.
Art: 10
I won't add much here, 10 is the rounded 9.5 that I gave it and this is because there was occasional CGI, which was really not necessary.
Music: 9
The music was also pretty interesting, I mean I haven't came across dubstep(!) in an anime ever before...
Characters: 7
There wasn't anything special about the characters, I'd say this was a mildy weak spot of the series. High schoolers falling in love and not understanding each other, there was a little bit of a harem as well - although I have to admit there wasn't much overreacting (phew!). What was interesting and suspensfull was the evolution of the parasites' behavior and that of the mc. The parents were given special attention too, which is very rare in anime (most mcs are missing one or both of their parents).
Enjoyment: 8
Nice job overall...
