Continuity mistake: In the scene where the police car is chasing Ben Affleck and Uma Thurman on a bike down in a tunnel, in one shot, the police car's flashing light on top is ripped off by the low ceiling. In the very next shot, the lights are still on the top. The next shot shows the lights are gone. (01:13:50)
Revealing mistake: Near the end of the film when we see Rhodes shoot Larry in the chest, you can see an outline of something underneath his vest, very obviously a device/squib simulating being shot in the chest. (01:15:15)
Continuity mistake: In the scene where Trout's gang burns the school and kills Sam, there is a part where Katherine runs into the sheriff's office then exits. A few seconds later, Katherine runs by a shop on which the name is reversed. Very obvious. (00:51:40)