Continuity mistake: In the scene where we see the room from a wider shot there is no rifle leaning against the barrel. We then get a closer shot of a man talking and there is now a rifle leaning against the barrel.
Other mistake: Just after the Royal Navy destroyer has sailed through and depth charged the area where the British survivors are, there is a shot of the churned up sea with sombre music playing, and the seagulls are flying backwards.
Revealing mistake: In the scene where Lancelot runs into and fights Arthur's ambushers, he runs one of them through with his sword. It is visible that he stabs his opponent past the body, but close enough for the appearance.
Continuity mistake: After 1st Sgt. Milton Warden breaks the bottle to stop the fight between Pvt. Angelo Maggio and Sgt. James R. "Fatso" Judson, he throws the bottle in a corner. In the next shot, he's sitting down with the broken bottle on the table in front of him.
Other mistake: In one scene Tyrone Power and his men survey a village where all the inhabitants have been killed by rebels. A dead boy is on a table and as the camera pans back he is wriggling his toes.
Continuity mistake: When Bugs is standing in front of the General's desk, the General has nothing in his left hand but in the next shot he is now holding a pencil.
Visible crew/equipment: After JD tells Schatze that Tom came to the wedding and he isn't wearing a tie, just as Schatze says, "Who does he think he is anyway, crashing my wedding," we can see the shadow of the boom mic drop into view on the wall, at the left side of the screen. (01:27:55)
Factual error: In the scene where Marcellus is being shipped off to "Palestine" on the galley - presumably from Ostia the port of Rome at the mouth of the Tiber - he is urged to hurry up his farewell to Diana by the galley captain because "we will miss the tide." This is the Mediterranean - there is no tide to speak of.
Other mistake: In the opening credits, Manuel Perez's first name is misspelled as "Manual."
Factual error: In the film, Houdini's family name is Schwartz. In reality, it was Weisz.
Character mistake: The hand bill identifies the company as Slipp-Skipp and Tripp. The sign on the door says Slipp, Tripp and Skipp.
Continuity mistake: When Bugs Bunny closes the door on Daffy Duck at the end of the cartoon, Bugs is holding his pencil upside down, but in the next shot he is now holding it the right way up.
Continuity mistake: Lieutenant Bowers questions the survivor of the first encounter with the alien, suspecting he might have just clobbered a love rival. The telephone rings; after it happens, the sheet in front of the suspect does a 180°. (00:09:35)
Continuity mistake: When we see the park where the wild cat is hiding, there is a sign saying "No Le Pate de Fois Grass", but when we see the sign in the next shot, the "Le" has disappeared.
Character mistake: On the sign outside Dr I.Q. Hi's headquarters, the word "Stratosphere" is spelled "Stratopere."
Visible crew/equipment: John Payne leaves a theater after getting into a fight after being tricked by actress friend Evelyn Keyes during an audition. As he walks out the backstage to the back entrance, the shadow of a crew member (possibly the camera operator) can be seen on the wall as Payne passes by. (00:31:00)
Continuity mistake: When Donald is sweeping the peanuts in front of Delores the elephant, he picks a single peanut off the floor and you can see there is nothing in front of him, but in the next shot a pile of peanuts has suddenly appeared.
Continuity mistake: When the elephant walks up to the bowl of clothes pegs, the number of pegs in the bowl changes between shots.
Continuity mistake: When Tom removes the packaging, you can see that it reads "Life with Tom by Jerry Mouse" on the front cover, but when we see Tom reading the book later on in the cartoon, the wording has disappeared.
Revealing mistake: In the beginning where Vincent Price is brawling with his business partner, his partner throws a pipe or bar at him. Price ducks and the bar hits something that the camera was connected to, because the scene jerks.