Continuity mistake: In the highway chase scene, JCVD rolls over the top of a car and lands on the ground on the other side. In one of the quick shots of him raising his gun to fire, the slide is back, showing that the gun's clip is empty. But a shot or two later, the gun fires several more times nonetheless, blowing up the car.
Suggested correction: In the split second where you can see the slide is open, the magazine isn't all the way inserted. He then slaps the bottom of the magazine to insert it in the gun before firing. They even add a sound effect when he does it.