Continuity mistake: On the truck cab's rear window, there is some sort of air conditioning unit installed. In some shots, such as the gas station scene where David Mann is on the telephone, or the railroad crossing scene, the air conditioning unit has a support structure to hold it in place. In the rest of the film however, there is not any support structure to be seen.
Continuity mistake: In the early scene when Harry walks across the street to confront the wounded robber on the street ("Did he fire six shots or only five?"), the shotgun used by the robber is lying several feet from the robber's hand, but when he reaches the robber, the camera shot shows the shotgun just a few inches from the robber's left hand. (00:13:00)
Continuity mistake: On Day 2, when the two officers go into the town's doctor's office, they leave the van with the driver's door way open, beyond 90 degrees, almost 180. The door didn't move to indicate it corrected itself as they went in. When they come out, the door is almost closed. And there has been no indication of a wind other than the helicopter, and that is supposed to be 1000 feet up and not even close to the office.