Generally speaking, I'm not much of a horror fan. They're fun to watch at night with some friends for the excitement factor, but as art they usually fail (with a few notable exceptions, notably Raimi's work). This movie comes close to being very good, and it would have been had the last 5-10 minutes been completely cut out. You see, the film develops the main character - a preacher who has lost his faith and now wants to expose Exorcisms as a sham - in a surprisingly effective way, using the handheld documentary filming style quite well throughout. The real stroke of genius, though, is that the movie keeps you wondering for most of the movie whether this girl really is possessed or if it's all psychological. You do see some freaky stuff, but it can be explained... kinda... or maybe not... well, maybe. You get the point.
But then, just as the movie seems to be ending on what I think is a hugely original and well-crafted tone, it does a 180, gives you a crappy and entirely random ending, and ruins everything that it built up to. Too bad.
In a sentence:
If you stop watching this movie about 5 minutes before the ending, it's a surprisingly original and well crafted bit of horror. If you see the copout ending, it's just another horror.
