Other mistake: During the final shootout in the saloon, young Joey yells, "Shane, look out!" Alan Ladd whirls around and his gun goes off. But the gun isn't pointed anywhere near the bad guy who is standing on the second floor balcony. Shane more than likely shot the furnace that was off to the right. Yet, the bad guy still manages to do a face plant on the barroom floor.
Revealing mistake: In the final Indian chase at the conclusion of the film, when a covered wagon rolls over, one can see the rope that was used to ensure it tipped over.
Continuity mistake: At the Scenic Tunnel Marilyn's lover writes a message to her on a postcard and places it back into the rack. She walks over and reads it but it isn't in the same place that he put it as the postcard next to it is different. (00:33:55)
Continuity mistake: At the end of the "Bye, Bye Baby" song the two girls are standing at the railing with two people in between them and the detective. When the shot cuts to their backs the two people in between the detective and the girls have disappeared.
Continuity mistake: When Audrey eats her gelato on the steps of the Spanish Plaza, if you look closely, the time is about 12:00 when she buys the cone. However, when she starts eating it, you can see that it's past 3:00.
Factual error: When Lt. Dunbar is being interrogated in the Commandant's office you can see a map on the far wall. It is a map of Germany dictated by the Treaty of Versailles which ended World War I because it shows E. Prussia separated from Germany and does not include the annexation of Austria and Czechoslovakia. These annexations were completed before the start of World War II in '39 and certainly before late '44, early '45 when the film took place. It is highly unlikely any German officer would have this map displayed not only because it's inaccurate but because it displayed the territorial losses brought on by the humiliating defeat of World War I.
Continuity mistake: There is genuine wartime footage of Spitfires of the the right type for the period, but other scenes have later (maybe even postwar) versions flying about.
Continuity mistake: While the close-ups showed heavy ice build-up on the doomed plane, the long shots showed no ice at all.
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.
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.
Factual error: In the movie, Houdini's death is caused by failing to escape from a Chinese Water Torture Cell following an injury with a prop sword. In reality, Houdini died of a burst appendix after being punched in the stomach.
Factual error: If we are to assume that the British cruisers were Dido class with 5.25" guns, the assertion that the Essen would outrange them by 5000 yards is pretty much true. However, in order for the Brits to launch torpedoes, they would have had to close to inside of 20K yards, well within range of their main guns. Thus said, if the British cruisers were any of their 6 inch gun class, there would have been no advantage in range.
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)
Factual error: As the team practices, the film shows the passage of time by using a calendar. The month of July ends on Thursday, the 31st, but August the first is shown to start on Wednesday.