Continuity mistake: When Ace is having a meeting with Green about him firing the cowboy, Ace stubs out his cigarette. In the next shot from behind Ace is still smoking, but when in the front he has no cigarette.
Continuity mistake: It is daylight when the car of Ace Rothstein explodes. However, it is night when he is being placed in the ambulance.
Continuity mistake: When Nicky goes to Sam's house to meet with Charlie, it's very light outside when he arrives. However when he leaves about four minutes later, the sun is setting. His entire stay at the house takes place during that scene.
Continuity mistake: About an hour and a half through the movie there is a scene with Nikki on a black and white TV. On the TV they are showing a photo taken by police of Nikki talking to another man holding a toothpick to his mouth to cover his lip from lip readers. That scene takes place later in the movie. The police have not yet taken that photo, we see it happen later on. (01:32:49)
Continuity mistake: When Sam is talking with Philip Greene after firing Ward, there is a shot of Sam facing the camera gesturing with his right hand not holding a cigarette, the a shot with his rear to the camera holding one, back to a shot facing the camera with empty hands again. (01:10:45)
Continuity mistake: After the very tense encounter between Ace and Nicky in the middle of the desert with De Niro watching Pesci leaving quickly, the distance between Ace and his car changes enormously in two different shots.