Continuity mistake: It is 1940. Two pilots come out of a house - one of them has just lost his wife and family in the London Blitz, the other is an RAF Squadron Leader. The door they come out of has a modern electric bell push - a post 1965 version, white rectangular box with a round button.
Revealing mistake: In the scene after the battle of Agincort, where Henry and his retainers are walking meditatively among the heaps of the fallen, if you look carefully, you will see one of the fallen with his head raised watching the procession. He then realizes that he is on camera and puts his head back down. It's near the edge of the screen so may occasionally be cropped.
Revealing mistake: When the toggle on the gun is pulled back that supposedly injures Captain S. Melly's fingers, it doesn't actually make contact with them.
Factual error: Outside the Territory Hotel, during the storm, and once earlier in the movie, the taxi cabs are shown with the modern "flip over" vacancy/hired signs that were not used then.
Continuity mistake: Near the end of the film, when the SEALs are in the inflatable boats heading towards the coast of Beirut, there is a shot from behind showing all the SEALs wearing black diving suits. But when the shot changes to a close up of their faces, you can see they are wearing camouflage fatigues, not diving suits.
Factual error: When the camera took a shot on a train coming to a station in Czechoslovakia, you can see electric cables above the train tracks. There was no such thing in Czechoslovakia as electrified trains in the 1940's. The electrification started in the 1950's. (00:01:05)
Revealing mistake: The cannons shown are firing blank charges, which produce no recoil. Recoil has been simulated by towing the guns backwards when they fire. The problem is, there is always a distinct delay between the discharge and the "recoil." The cannon also seem to largely fire explosive shells. At no point do we actually see a cannon ball rolling or bouncing along the ground or into any group of soldiers.
Factual error: An old man appears with children following him. This is supposed to be pedagogue Janusz Korczak. It appeared as if he was just wearing a suit and a Jewish arm band. In the Warsaw Ghetto, Mr. Korczak never wore an arm band and wore his WWI Polish Army Uniform, both as acts of defiance. He was beaten and almost put to death (he had connections) for not wearing an arm band so having one on in the movie is inaccurate.
Factual error: The film was released in 1958 but depicts a 1943 World War II mission in the Pacific by a US submarine capatain played by Clark Gable and his first officer played by Burt Lancaster. In two separate scenes the crew listens to a "Tokyo Rose" broadcast on radio and the background music is "Kiss Me Once, Kiss Me Twice, It's Been a Long Long Time" by Sammy Cahn and Jule Styne. The song was not released until September 1945, one month AFTER the end of the war in the Pacific in August 1945. The song was famous for celebrating returning troops and therefore also makes no sense in the context of 1943.
Factual error: After Hardy dies and they're going through his possessions, a football scarf is pulled from his kit bag. The scarf has a Sunderland AFC badge. The film is set in World War II. The badge on the scarf was introduced in the 1970s.
Revealing mistake: In one of the river flooding scenes after the dam bursts, you can see a modern day vehicle (most likely a pickup truck) for a few seconds on a highway next to the river. (01:50:30)
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.
Factual error: At the very beginning of the film, Gunny Highway learns that he's being reassigned to the 2nd Marine Division. The 2nd Division, located at Camp Lejeune, North Carolina, is situated on the NC coast; there are no mountains in the immediate vicinity. However, when the Gunny trains his platoon, he does so in the hills of another Marine training camp located in California. There is a big difference between California and North Carolina.