Room 237 isn't some quirky study of a group of people hung up on a certain movie, but a movie about the power that certain movies possess: a real, troubling, dominating power not just to inspire, entertain, or annoy, but to corrupt the minds and muddle the thoughts of its viewers. It's this uncanny, irreconcilable power that animates the doc. Cinema's the corpse in the bathtub, the skeletons in the ballroom, the elevator full of blood, the guy in a dog costume blowing a ghost in a tuxedo.