Continuity mistake: Near the end of the movie after the fake FBI agent shoots the sheriff, there is a scene where you see the sheriff's dog lying next to him. When the dead sheriff is shown again a few minutes later there is no sign of the dog or even dog footsteps in the snow. (00:09:00)
Continuity mistake: The house that the main characters live in is shown very early in the movie. We see the people looking out of a large window in an upstairs bedroom, which faces the front driveway. But that window doesn't even exist when they show the outside of the house.