Continuity mistake: In the scene where Johnny and Kamal are going out for a night on the town, they first walk into the place and they go to their seats. Notice the Reserved tag on their table -- when they sit down, it's gone.
Continuity mistake: In the scene where Johnny calls the nurse, at the end of the call, the nurse hangs up. Then in the next shot, Johnny and Kamal are just sitting there laughing. There is no way Johnny could have hung up the phone that fast.
Continuity mistake: In the scene where Johnny and Kamal steal the cab, Kamal closes the door. But in the next shot he closes it again.
Visible crew/equipment: When Johnny and Kamal escape the hot dog place and Tony pulls up in his car he screams at the two guys to get in the car. As the guy is running around the car, check out the driver. It's clearly not fat Tony, but a skinny stunt driver.
Audio problem: In the opening scene, where Johnny and Kamal are arrested and they're making their way to the police station with the cops, notice the cop screaming, the words don't match his mouth.