Continuity mistake: In the beginning of the movie, during the big fight, Frank grabs Mikhail Gorbachev and smashes his head through the wall. The guy stays there but at the end of the fight, when Frank is about to jump out of the window, it shows him again. The hole now is bigger and not only consumes his head but all the way to his waist.
Visible crew/equipment: When Drebin chases the doctor out of the hospital, the doctor gets a car, while in the background, Drebin falls from the ladder. Dreblin then emerges from under the car. The doctor drives off, and Drebin enters the foreground. Look in the windscreen of the car Drebin emerged from. The top of a man's head with grey hair appears at the end of the shot, thinking it's over. It is spotted most easily when viewed in slow motion. This is the stunt double that dropped from the ladder.