There were lots of twists and turns in this well written, well acted film. It'd be easy to dismiss this as predictable (which it isn't), but it's just quirky and suspenseful enough to keep you watching. It's not your usual suspense film: there's gore, comedy, and several plot twists, so it will probably not appeal to a large group of people (plus most of the action takes place within the confining space of an elevator). Even so, the unusualness of it appealed to me; I've already rewatched the last 10 minutes of it (and it's one of those films that you need to watch through the end of credits). Give it an open-minded watch!