Revealing mistake: When the FBI agent is in the room of the court medic to get the cause of death, in several shots the sliced up corpse is breathing. (00:27:00 - 00:29:30)
Continuity mistake: When Cory is following the lions' traces he gets off the sled with gloves on, then he makes the gesture of taking them off (not actually showing). The close up shows him with no gloves on, then wearing them, then not wearing them. (00:12:00)
Other mistake: At the end of the movie, when Cory is in Natalie's bedroom, Cory stops and looks at a picture of Natalie and his daughter wearing a high school graduation cap and gown. Cory said his daughter was only 16 when she died so she would've already been dead by the time Natalie graduated. (01:36:00)
Factual error: In the credits, "they" would like to thank "the city of Landers, Wyoming." It is Lander, WY, as seen in the opening shot - not Landers.
Continuity mistake: When Jane shoots the guy in the trailer, there is no blood on the wall behind him as he slides down. When she approaches him and removes the shotgun, streaks of blood appear.
Factual error: Ben states that the temperature is -6'F. When the officers drive to Matt's camp the gravel road is quite slushy. This would not happen in freezing temperatures. (01:03:10)