In the initial chase scene, the Ferrari and the police cross a street with green light. In a camera angle change from the other street, the light is green too.
In the Ferrari car chase in the beginning of the movie, the Ferrari logo disappears and reappears four or five times.
Early in the movie, when Tom Beck is about to shoot at DeVries speeding in a Ferrari, he throws his jacket haphazardly over his car door. In the next shot his jacket is very neatly folded over his car door.
Beck gives Gallagher ONE Alka Seltzer, which the extraterrestrial nibbles at. Beck tells him that the tablet should be dropped into the glass of water, and Gallagher does it. In the next take, Gallagher is dropping another (this time entire) tablet to the water.
At the end of the first car chase Sanchez and some of the other officers train their shotguns toward the speeding Ferrari of DeVries. The next shot shows these officers standing with their guns at their side, while in the shot after that, their guns are once again pointed towards the Ferrari.
Masterson's M72 LAW rocket would not have exploded so soon after leaving the launch tube. By design, the LAW rocket must travel 10 meters before arming itself. If it strikes a target closer than 10 meters, it will not detonate.
The Porsche-Cadillac chase uses the same corner shot from two different angles as though they are different corners.
Just before Beck and the other police officers are ready to shoot at the speeding Ferrari, the camera follows the Ferrari and we see the police from Jack DeVries point of view. At the top of the hill - before Beck starts shooting - you can see a gun going off before the actual shooting starts.
Shadow of camera car visible in first car chase.
In both cuts of the stairs chase in Neptune Mannequins building, the boom mic is visible.
At the car dealership where Eddie is shot and taken to the office, when the door opens to reveal the dying Eddie, the guy in the white suit looks down before Eddie's body actually drops to the floor.