Continuity mistake: When news on Robert De Niro not having a casino license first hits the airwaves, the news broadcast displays a still picture of Joe Pesci having a conversation with his friend Frankie. The picture that they use is when Pesci and Frankie have tooth picks in their mouths because they don't want FBI agents lip reading what they are saying. But that didn't happen until later on in the movie. So how could they have displayed a picture of a conversation that hadn't taken place yet?
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: 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)Floyd1977