Continuity mistake: Outside the hospital McCluskey punches Michael. A few days after the episode outside the hospital, Michael shoots McCluskey and Sollozzo at the restaurant, but there is no mark on his face where he was hit. Then in Sicily when Michael meets Apollonia for the first time, there is still no mark on his face, but suddenly at Apollonia and Michael's wedding, he has a large mark on his face.
Revealing mistake: When Sollozzo picks up Tom Hagen after killing Luca Brasi, you can easily tell that the snow falling is made of thin plastic.
Continuity mistake: Michael shoots McCloskey in the throat with a black plated gun. The shot following shows Michael pointing a silver plated gun against a black background, so they probably needed something to stand out. Michael then finishes McCloskey with a black plated gun.
Continuity mistake: When Michael is sitting with Sollozzo and McCluskey, the owner (presumed owner) of the restaurant (shown from the rear, walks behind the bar to ring up and put a check in the register, he is smoking a pipe. (in his mouth) But yet a split-second later from a front angle there is no pipe in his mouth, hand, or anywhere near him.
Character mistake: In the scene where Vito is buying fruit right before he is shot if you listen closely you can hear Vito ask for 3 oranges (the subtitles say the same) but the produce seller only puts 2 in the bag.
Revealing mistake: When being transferred to another room the supposedly unconscious Don pulls his left arm up so it won't hit the door frame.
Suggested correction: He's shown to be awake when Michael is talking too him moments later, albeit weak. He was probably woken up by the movement before this point, so he was conscious enough to move his hand.
Continuity mistake: When Sonny gets the vest with the fish, they move between shots.
Factual error: Michael had his meeting withe Solozzo around Christmas of 1945. On the way to the meeting, the car made a U-turn on the George Washington Bridge (GWB) to throw off anybody who might be following. At the time, the GWB had four traffic lanes, two in either direction. The median between the two set of lanes was about 20 feet of steel mesh, making such a maneuver impossible. The median was filled in to add two additional traffic lanes in 1946. At that time, the u-turn would have been possible.
Continuity mistake: At the restaurant, Michael, Sollozzo, and Captain McCluskey have just sat down at the table and the waiter comes over to take their order and pour wine. McCluskey asks Sollozzo what's good to order, and he recommends the veal. Before the waiter leaves the table, McCluskey is suddenly eating his dinner, even though they just arrived. By the way he is using his knife and fork, it is obvious that he is eating an entree, and not a salad or an appetizer.
Other mistake: As the camera pans in on Woltz's mansion right before the horse's head scene, his bedroom is on the second floor. However, the windows in his bedroom show a courtyard in the background. The horse's head scene was filmed in a dining-room-turned-bedroom at a Guggenheim mansion on Long Island. The Guggenheim dining room is located on the first floor, as shown in a February 2022 episode of Antiques Roadshow.
Factual error: In the establishing shot of the movie producer's mansion, a car in the driveway is suppose to be a 1937 Cord, but actually it is a replica produced between 1968 and 1972. Real Cord cars had bug eye headlights that cranked out of the fenders. The replicas had fixed glass covered headlights in the fenders.
Revealing mistake: When Tom is visiting with Waltz, it is a body double and not Robert Duvall walking outside on the way to see the horse.
Continuity mistake: When they leave to kill Pauli it's light outside, when they are driving and Clemenza says that they to get more mattresses it's dark outside, when they stop to kill Pauli it's light again.
Continuity mistake: When Woltz shows Tom Hagen his horse, Khartoum in the stables, the horse has a prominent white star on his head. The horse's head in Woltz's bed later that night has no such star, the head is all black.
Continuity mistake: At the end of the shot where Al Neri shoots Emilio Barzini's bodyguards, the one on the right is still in the process of falling and hasn't hit the ground yet before it cuts, but in the next shot, he's already on the ground and not moving.
Other mistake: When Al Neri shoots Emilio Barzini's bodyguards, they're both only shot in the torso, but when they're on the ground, there's only blood coming out from under their heads.
