Continuity mistake: When Michael and Shorty are having lunch after Michael is released, he empties the contents of the envelope onto the table. A bit later he puts everything back into the envelope, but the bullet remains on the table under a napkin. Later in the movie, Michael empties the envelope and the bullet is in it.
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.