Character mistake: During the dancing girl scene, as they are singing the praises of Kane, the girl to the immediate right sings out of time with the rest of the dancers during the line "His favorite son." Even though she forgets to sing the line, she can be heard singing it a bit too late. (00:41:00)
Continuity mistake: In the scene with the lovely dancing ladies, Cotten blows cigar smoke just before a cut to him from the opposite angle. From this angle there is no smoke. This takes place just before Wells throws his jacket to Cotten.
Continuity mistake: When Kane and Susan are speaking in their mansion, Susan is busying herself with jigsaw puzzles. The wide shot shows the jigsaw puzzle almost completed, but Susan's close-up shows the jigsaw puzzle in pieces.
Revealing mistake: To save money during the beach picnic scene, Welles used stock footage from King Kong (1933) for the jungle background. You can quite clearly see pterodactyls flying in the background (confirmed on DVD commentary).
Factual error: When we see the Spanish newspaper reporting the death of Kane, the title says "el Sr. Kane se Murio". No self-respecting newspaper would omit the accent on "murió". Also, Kane was supposedly a worldwide household word, so he would never deserve "el Sr.". Finally, the colloquial "se" is out of place in a printed title such as this. The title should simply be "Murió Kane".
Revealing mistake: When they are inspecting the statues at the end of the movie, somebody touches one of them. It wobbles as if it was made of something else than stone.
Revealing mistake: When the Parrot (or whatever bird it is) cries in a close-up, one can see straight through his eyes onto the sea in the background. Probably a mistake in an optical printer.
Factual error: When they are driving to the Everglades for a picnic, the sea is at their left. As Xanadu and the Everglades are on the Gulf coast, the sea should be at their right.
Suggested correction: That depends on which direction are you filming, north-south or vice versa.
Continuity mistake: When the dancing girls start singing to Charles Kane, there is a frontal shot of Kane sitting next to a man wearing a hat. When the shot changes from being in front of them to being behind them, the man is suddenly no longer wearing the hat. When the shot changes back, he is once again wearing the hat.
Visible crew/equipment: When Kane is talking to Leland, after the campaign is over, there is a low angle shot looking up at Leland from Kane's feet. The shadow of the camera can be seen on Kane's right leg until he moves.
Revealing mistake: As the camera moves back (or is it forward?) through the Kane household at the beginning of the movie, you can hear the sound of the camera on the track.
Audio problem: In the scene where Charles Kane slaps his wife in their tent at the Everglades, the sound of the slap is heard before his hand reaches her face.
Continuity mistake: The scene in which Kane's wife is leaving him, shows one of the suitcases open in a medium shot while all others are closed. She heads for the bedroom door and the shot cuts back wide to Kane standing by the bed. The previously open suitcase is now closed.
Audio problem: When Gettys is leaving Susan's apartment, there's one shot where Kane is shouting at him, but his lips aren't moving.
Continuity mistake: When Kane is talking to Miss Alexander on her sofa the dramatic lighting changes from the left side of his head to the right. During close ups his left site is lit and his right side is in the dark. When the shot is from the front, showing both actors, Kane is lit from the right leaving the left half of his face dark.
Other mistake: In the extremely low angle shot where Leland is drunk talking to Kane, a black visible object is stuck to the frame of the camera, bottom left. As Kane walks out of the shot, the camera pans up and it is gone.
Audio problem: When Kane is talking to Mr. Carter about what the Inquirer should be printing, we see a shot of Kane talking from behind. His mouth movements are slightly off from the audio.
Visible crew/equipment: When Mr. Thompson goes to the Thatcher library, he walks through a door and the camera follows him. Just before the shot ends, the camera casts a shadow on the left wall.
