Memento and Inception got nothing on this one

The first hour (and 5-10 minutes) of this movie is as good as any horror flick I've ever seen, but then the twists start happening and good lawd, they never stop. I won't spoil it, but they may just go one twist too many. While it adds to the mystique of the film, the final 10-15 minutes drags on intolerably.