Continuity mistake: In the scene containing the Jitterbug contest, the waiter removes Jerry Lewis' dinner plate to give him champagne. After a cut away to the emcee, the waiter again removes the same dinner plate.
Factual error: In order to make Polyphem drunk, Ulysses and his men produce 'wine' by treading on grapes. Only thing is: without fermenting the stuff for a few months, all you get is grape juice, which is not even remotely intoxicating.
Continuity mistake: When Marilyn Monroe tries to untie the raft and Robert Mitchum can just catch the rope it the river flows from left to right. Later, when they take off again together, the river flows from right to left.
Continuity mistake: At one point bus driver Frankie Howard shins up a signpost to read road directions in the fog. The sign says WET PAINT and he slides down with his uniform jacket streaked and ruined. However, several minutes earlier, as he leans forward to peer into the night, Howard is already wearing the paint-stained jacket.
Visible crew/equipment: When Henry Hobson enters shop at start of movie, there is somebody wearing spectacles hiding behind the shop counter that is covered in shoes and boots. (00:03:43)
Visible crew/equipment: When William Holden is visiting Frederick March in the Admiral's cabin a boom microphone is visible near the air conditioning ducting in the ceiling. A shadow is seen, then the microphone drops down into the shot. The microphone moves a bit and then is raised.
Continuity mistake: The two workers are being dismissed by their boss after their 'too zealant' repairs of the streetcar. Shot from behind when he stops them as they walk away, you can see him place his right hand flat on the desk, directly on the wood. Next shot and his hand is in a different position and on the papers. (00:05:30)
Plot hole: Helena is ordered to fly or be thrown off the tower, bearing the brunt for Simon's failure. But the flying apparatus is still up there, and so is her servant who was going to secretly operate it so that Simon could pretend to fly around. All she needs is right there in front of her. She's supposed to be cunning and resourceful, and she could have saved her life simply by following the original plan.
Continuity mistake: When Frisky Puppy is looking inside the box at the dump, the fence behind him is grey, but in the next shot it is white.
Revealing mistake: Many of the cavalry soldiers were carrying M-1 Garand rifles (WW2 era rifles).
Continuity mistake: When Foghorn Leghorn enters Miss Prissy's house with the present and flowers, he closes the door behind him. But when Prissy asks Foghorn to go outside and play with her son, the door is open without no one having touched it.
Continuity mistake: When Tom rushes up with his knife, fork and dish to get his dinner from the cook, you can see that Tom's knife is pointing straight but in the next shot it is now pointing to the right.
Continuity mistake: When Tom attempts to squirt Jerry with the bottle of seltzer, Nibbles sets the freezer to Quick Freeze which freezes the floor and Tom is left frozen. You can see that when Tom is frozen, the bottle leaves an icicle of frozen water, but when Jerry and Nibbles dance around Tom at the end, the icicle has disappeared.
Continuity mistake: When we see Hans walking down the rope from the boat, he's carrying plain pink cloth. But when we see Hans the next time, the cloth now has white spots on it.
Continuity mistake: When Jerry and one of the puppies hear Tom whistling during the thunderstorm, you can see that there is a newspaper by the puppy when he and Jerry look out from their shelter, but when Tom falls into the river, we cut back to Jerry and the puppy and the newspaper has disappeared.
Continuity mistake: When Porky tells Daffy to arrest Nasty Canasta, you can see the window next the door has four panes of glass, but when Daffy challenges Canasta to a fight, the number of panes has increased.
Continuity mistake: When Sam is standing by the Powder Room, he is holding a sword in his right hand. When Sam sees Bugs throwing a match into the Powder Room, the sword has gone.
Continuity mistake: When Spike threatens to kill Tom for giving him the hiccups, you can see that there is a burst paper bag by Spike and there is nothing in Tyke's bed, but when Tom crashes on the ground after climbing onto the house's guttering, the paper bag has disappeared and there is now a pillow and blanket in Tyke's bed.
Continuity mistake: In the scene set during the King Arthur and the Round Table era we see the end of a battle scene. The camera pans in on some dead enemy and we see a man in a helmet face down. The scene then changes but comes straight back to the dead enemy. The man in the helmet has turned away as if to survey the scene before him. Within a second he turns his head back to the original "dead" position. (01:19:30)
Continuity mistake: When Tom is playing with a ball of yellow wool next to Joan, look at the chair next to the table and you can see that George is missing, but in the next shot he is back in the chair.