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.
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.
After Hank shoots Lou's wife in the kitchen, the camera shows Jacob walking into the house, then Lou's body on the floor with a puddle of blood around his head. If you watch closely, you can see Lou's left eye twitch.