Continuity mistake: When Libby goes to the BMW dealer, the dealer says the address is 20 Oriole Terrace. When Libby is driving down Oriole Terrace, she passes a house with four digits in the address.
Continuity mistake: When Heather first picks up the bundle of sticks she carries them to the river. During this she steps over a log on the ground and if you look closely you can see the black bag containing the guy's teeth fall out but when Heather opens up the bundle it is still there. She couldn't have put it back herself.
Continuity mistake: The writing on the tape that Alice sends to Hank keeps changing every time you see it through the film.
Continuity mistake: The entire bar scene at the beginning of the movie contains numerous continuity errors for the props (e.g, lamp, jar of pickles) and background. The background changes and it is difficult to see what is being shown. In some views, there appear to be some kind of pillars or wooden rails/posts that are practically up to the bar and/or above Casper's head. At times, the ceiling looks domed with pictures arched/curved from the top of the wall to the domed ceiling. There is an overall lack of continuity in the bar scene.