Parasyte The Maxim
 

I haven't watched Patasyte The Maxim yet, I definitely will though. It looks great.

I'd recommend watching Another. It's a very atmospheric anime. Interesting story and plenty if gory kills. It's probably the best horror specific anime around.

I also recommend Higurahi AKA When they Cry. A very complicated story but full of crazy disturbing moments. At times its slow paced and creepy and other times just pure nightmare fuel. At least the first season is. The second season kinda drops a lot of the horror elements in order ti explain the plot

Still worth watching though!

I rarely like Anime. However Doomed Megalopolis was fantastic inspire of the rape scene. Also Grave of the Fireflies is horrifying, but because of its reality. Be prepared to have a hard time watching it.

Tokyo Ghoul and Attack on Titan have about the same balance of horror and action as Parasite the Maxim. The last Vampire Hunter D movie is good.

Re:Zero has some good horror moments, especially in the beginning, for a fantasy story inspired by gaming.

High School of the Dead was a great zombie series.

Deadman Wonderland was good.