Far better than I remember it, goes up a whole star and a half. The second half fails to live up to the brilliant first half, but its still bloody good. At the end of the film I felt the most sorry for Teddy, though I think that could be the idea.
I'm not a big horror fan, but this one has to be at least one of the most effective horrors I've seen. It uses most tricks in the horror book, except tits and gore, and they work well. The slightly over the top ending lets it down a tad.