I would give this movie about a 6.5 out of 10. It is entertaining, the central plot is somewhat original, and I was a fan of the cinematography. It's rather visually appealing.
That being said, it was definitely not all that I'd hoped for. One of the other reviewers said the filmmakers thought they were making a smarter movie than they actually were, and I have to say I agree with that. The plot concept and the idea of anamorphosis is rather original and has a lot of potential. Yet I feel as if the filmmakers thought that this concept was SO ingenious that they didn't need to develop other parts of the film. The back story, for example, is explicated through memories and conversations so that the past is never wholly or even adequately revealed to the audience. What's worse, the character development is completely lacking. Willem Dafoe, who acting-wise does a nice enough job, reveals certain attributes about his character in very subtle ways. The rest of the characters, however, are pretty one-dimensional and used strictly as plot devices. And, as is common in film, the police work done in the film is a bit illogical.
All and all, the film is all right. I'm a big fan of psychological thrillers and I was certainly on the edge of my seat for a great deal of this one. It's pretty instantly gratifying, but if you take a few minutes to think about what you just saw, you might see some of the flaws I just mentioned.
PS - for those of you who are squeamish: there is little/no actual violence, but plenty of gross dead bodies.