Continuity mistake: During the fight with Breck, Butt falls inside the ladies' room with both feet inside the place. A shot later, they're outside.
Continuity mistake: When Buster and Billie are at Slim Mim's Jamboree near the end of the film, Buster is wearing an open-collar shirt. When they step outside to get some air, it changes to a button-down shirt and tie.
Continuity mistake: When the boy stabs the man in the back with an ax while they're chopping firewood, the position of the ax changes between shots. In the first shot, the ax is vertical because the boy is behind the man. In the next shot, the ax is horizontal as if the boy is on the right side. (01:06:53)
Continuity mistake: Nini's mother fishes the telephone out of the bathtub. A naked little boy prances around the room and Christian De Sica is in a quite recognizable position, leg up scrubbing the sole of his foot. Cut, and De Sica is now simply sitting in the tub as if nothing happened. (00:22:00)
Continuity mistake: Gene Hackman returns a second cookie to Harrison Ford's dish that he hadn't taken - or perhaps it's the same cookie he picked up and returned a moment earlier. Either way, the cookie had suddenly appeared in Hackman's hands going from one shot to another. (00:30:35)
Audio problem: As McQ is attempting to escape from the hoods by driving down the beach in a 4-door automatic Belvedere, you can hear manual transmission upshifts occurring.
Factual error: The film is set in the 1920's. When the policeman appears towards the end of the film on his helmet is a post-1952 helmet plate with the crown of Queen Elizabeth II.
Other mistake: The Amazon's queen says she pierced Dharma's chest with her spear/lance but he's shown dying from a side wound.
Factual error: At the end of the movie, Mame takes Peter with her on a trip to Siberia. However, at this point in the timeline, it's the late 1940s, meaning that Stalin was still in power, so even Auntie Mame would be crazy to think of vacationing in Russia. Not to mention the difficulties of getting Peter a visa to travel to the USSR at the last minute. (In the stage version, the destination was India, rather than Siberia, which makes a lot more sense).