Continuity mistake: When the lottery winner is going to die, the beer bottle he takes out of the fridge moves all over the place. It even vanishes a couple of times.
Revealing mistake: When the camera shows the coffee cup in the cop's car, you can see the ignition is in the off position (00:09:16)
Revealing mistake: When Nora's son gets killed, we can see the boy under the falling piece of glass. But in the shot where this piece is just about to smash him, you can see on the DVD edition that there is a dummy instead of him because his arms are too long relatively to the whole body and also the hands are obviously not human. (00:41:20)