Continuity mistake: When Eddie Murphy is getting the bananas from the waiter in the hotel, the bananas he gets are straight. When he places the bananas in the tailpipe of the detectives' car, they are curved.
Continuity mistake: The whole time sequence in the last part of the movie is messed up. After trying to nab the bad guys at the hotel, Tom Selleck goes home and puts his son to bed, then is called back in to work, and then the rest of the film is supposed to be the same evening, but it was already late night.
Continuity mistake: Charlie is in the clock store with Barney. A sign on wall says "do your Christmas shopping now". Different letters are missing in different shots of the same scene. (01:16:00)
Continuity mistake: At the end, after Mahoney kisses Karen, she takes off her hat and the position of her fringe changes between one angle and the other.
Continuity mistake: In an early scene, the bartender and the bar owner's wife are driving in the rain, at night. The car is a large Ford: at one point, it becomes a mid-sixties Volvo 122, then is shown as a Ford again.
Continuity mistake: In the first 1968 section, where Noodles rents a car and drives back to his old neighbourhood, watch the background of the wide shot as he is stopping the car. In the close-up that follows when Noodles gets out, two girls have appeared, hanging around a doorway, who were not to be seen the moment before.
Continuity mistake: When Jeff Bridges and Rachel Ward are on the beach in the grass hut on the video version you clearly see the overhead boom mike swinging back and forth to face the character who is speaking at the moment. This continues through the whole scene.
Continuity mistake: At the beginning of the film, when Johnny is first climbing the stairway to his apartment, he climbs a flight, then there is a dissolve to imply that it's a very long stairway, and he's shown climbing another flight. You can see the ground floor only one flight below after the dissolve.