Tommy cuts off the left ear of the man in the barber's chair, but the ear he drops into the plate of spaghetti is a right ear.
The mob boss' glass of red wine turns into a glass of water, and also swaps hands.
The mob boss's forks, in the Italian restaurant.
After Tommy is shot, he staggers away from the corner of a building twice - once in the shot from above, then again at street level.
When Tommy shoots one man, the blood spray comes from in front of man.
Towards the end, when Tommy leaves the building, the elevator door closes though his leg is in the doorway.
The movie states at various points what year it is, but many of the vehicles driving around are newer than what time frame the movie states.
In one scene, Fred Williamson is seen walking down the sidewalk. Look closely, and you can see a length of mic cord trailing from his leg.
After Tommy is shot he gets in the cab and appears to close the door with his foot but the crew member's hand is visible helping him close the door along with a reflection of a camera in the cab's window.
Shadow of the camera on the blind guy as Tommy is staggering up the street after being shot.
When the police officer follows Tommy across the street after he leaves Tiffany's, a passenger in a truck in the background can be seen waving frantically at the camera.
When Tommy's henchmen are being assassinated, a bearded one wearing a Gray Apple-Jack hat is shot on the street and ends up dying on a two-wheeled cart. His dying act is not to clutch where he was just shot, but hold on to his rather large Apple-Jack hat as he rolls down the cart.