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.
Continuity mistake: In the scene where Frank is in the driving school car chasing the doctor, right after Frank says, "I know a shortcut. Turn left here", we see two brief shots of the doctor's car, one from the inside of the car and the other from the outside as he is turning around a corner. In both shots the rear window is shattered. However, it is only four shots later that Frank shoots at the doctor's car, shattering the then intact rear window.
Continuity mistake: Just before Frank accidentally nudges one of the fishermen into the river with his car, if you look in the background there is a police car. In the next shot of Frank getting out of his car on the pier, the police car is now noticeably much closer than in the previous shot.