The tension keeps building and it comes off as a really expensive Twilight Zone episode. There's no real pay off or clarification as to what is happening and the audience is meant to be just as in the dark as the characters. I agree with some of this starting happening, especially the beach scene at the beginning, I'd probably head home quickly. Oddly placed long dialogue scenes muddle the pace. Interesting soundtrack and camera shots, good cast, but keeping the audience tense for over 2 hours with little payoff seems like a cop-out. Worth watching, but I doubt rewatching ever again.