Continuity mistake: When the guys visit Kenny in prison, they put their fists on the glass, the angle of their fists changes between shots. Most notably Scarface (on the right).
Visible crew/equipment: As Jackie Chan begins to fall from the ceiling onto the banner after the climax you can see about 4 (maybe 5) crew members on the balcony to the right of the screen getting the high angle shot. (01:28:35)
Continuity mistake: When Danny gets shot at the end of the film, his paper flies out of his hand. But the very next shot of him shows that the paper is still in his hand being held over his head while he falls backwards. In one of the following shots the paper is back on the floor, but it's on the opposite side it should have been when it flew out of his hand. It's all shown in slow motion and it's very obvious.
Continuity mistake: When Samir is shot and falls into the pool, he falls in facing up. But the underwater angle shows him land in the water face down. (01:42:45)
Continuity mistake: In the scene where the Monte Carlo is battling with the Camaro, they go off road into a field. During a certain shot, the Camaro has to jump a hill and it goes airborne. While it's airborne, you can see the entire front end is destroyed. However, after it lands, you can see the front end of the Camaro is in excellent condition and it remains intact for the remainder of the film. I would guess that they used at least two Camaros for the film. (00:26:10)
Visible crew/equipment: When Vincent and Sam are running through the ice rink's changing rooms to get the case off Gregor, the camera passes a mirror. If you pay attention, you can quite clearly see the boom operator wearing a blue and white checked shirt in it. (01:43:40)
Revealing mistake: When there is a car crash, and a motorcyclist flies over one of the cars, as he rolls towards the windshield we see the whole windshield intact. Then when the motorcyclist rolls and hits the windshield, large cracks are clearly visible, way before the man hits the glass. (01:00:30)
Other mistake: While the fire on the oil rig burns all around, Mr. Freeze grabs Belson, then orders him to go find Barbara (to do the transplant). When it cuts to a closeup of Freeze, the reflections of Belson on Freeze's eyeglass lenses are not reversed as they should be. (00:53:00)
Visible crew/equipment: When the Nihilists are ordering food at the restaurant, you can see the reflection of the camera and cameraman in the window behind them. Watch as the scene pans around and you can see the camera and the cameraman move as well. Could the person behind the camera be Roger Deakins? (01:34:20)
Continuity mistake: When Julia is explaining the conspiracy to Rick in the stairwell, the position of Rick's hands in front of his face change between shots. (01:03:25)