At the end of the scene where Jim holds Flaco and his crew at gun point, we see both Jim and Mike walk towards the car. In one shot we see Jim insulting Patty while Mike has just closed his passenger door, sitting inside the car. In a following shot we clearly see Mike standing outside his door waving to Letty while opening it.
In California, only the rear license plate has registration stickers on it. On a couple of occasions, registration stickers appear and disappear again on the front plate on Jim's Ford Interceptor.
The length of Mike's facial hair varies between shots, especially in the scene at the end of the film when he's sitting in the car outside the dealers' house.
In the scene where Jim discovers he has been rejected by the LAPD and goes into a violent rage, there are several inconsistencies with the shots of the traffic behind his Ford. For example, one shot shows Jim marching up to the car on his right, a bus passes the left side of his car. The following shot shows the same bus behind his car. Another following shot then shows no traffic behind his car for at least 100 meters.
When Jim learns he has been rejected from the LAPD, Mike suggests it's pretty obvious what has happened, at which point Jim raises his hands in confusion. The following shot shows Jim's hands firm on the wheel before raising them and shaking his head in the same manner.
After Mike shoots Jim, he leaves his pistol in the car with his fingerprints still on it. Assuming the police will eventually discover the crime, they will have no problem linking Mike to it because of his prints, especially since he already has a police record.
Mike and Jim both make references to the Immigration and Naturalization Service (INS), when that agency ceased to exist in March 2003, two years before the film was made.
Throughout the movie, none of the guns eject any empty cartridge cases when they are fired.
The Gear lever in the car which Jim is driving changes from the park position to the drive position, while he's in motion.
When Jim and Mike are driving in the car, Mike opens two bottles of beer for himself and Jim. However you can see that Jim's beer has already been opened and is missing its crown cap.
When Jim and his girlfriend walk to the car where she tells him she's pregnant, you can clearly see a shadow of a cameraman on the billboard behind Jim on the left of the screen.
[Spoiler] Just after Eddy is murdered in the bar, Jim and Mike run to Jim's car. As they are driving away the camera and a crew member's shadow is clearly visible on the sidewalk.
In the scene where Jim's car gets pulled over by two cops, a shot showing Officer Leo walking up to the car reveals a crew member visible to the left of the second officer (far left of the screen).
When Jim and Mike go to see Toussant he uses his key to open the door however you can see that the door isn't tightly shut.