This movie's flaw: Eric was annoying and unlikable
So I just watched this a couple nights ago, and I found it disappointing. It just could have been so much better, but it was completely average and even boring at times.
I just didn't care about Eric. I got irritated with him every time he'd try to act "cool" or superior to people by spouting off random movie facts. He was just really annoying and not very likable. By the end of the movie, I didn't sympathize with him or even care about what happened to him.
There were a few moments, though, where I did genuinely find his character fascinating. Like in the scene where he chases the prostitute, and then she falls on the fence and is accidentally stabbed in the neck. I thought that was a really creepy scene because then Eric proceeded to drink her blood from her wound. I also thought the scene where Eric painted his face was interesting. And I liked the scene where he came back home and started talking to his Aunt's urn. These scenes made his character more complex and sympathetic. It's too bad there weren't more scenes like these throughout the movie.
So yeah, I think this movie could've been a lot better if they made Eric less annoying and focused more on the movie being a character study of him going insane. Also, that masturbation scene was really awkward to watch. I'd get rid of that.