Factual error: The U.S. Paratrooper uses his "clicker", and the German answers with a "double" click-click - click-click. The Paratrooper stands up, and the German soldier shoots twice with his Mauser K98 without pulling back the bolt between shots, which is impossible.
Suggested correction: There could have been another German soldier present who fired as well.
Visible crew/equipment: During the initial phase of the final assault, a row of men with their backs to the camera is shown. One of these men (right of the center, with a bandaged head) is actually a dummy positioned at the spot where the wall is blasted a few seconds later. (02:29:35)
Revealing mistake: In the scene where Themistocles first talks to Queen Gorgo, in the background you can see several extras, one of which is wearing obvious sneakers. (00:18:35)
Factual error: At the end of the movie, a Willys is shown with an inscription on the back: "Left hand drive vehicle." The scene takes place in Midway or Pearl Harbour. This inscription on the vehicle was only for the US forces in England beginning in 1944.
Factual error: Chris Kyle did not make Chief after his first deployment. He made Chief during his fourth deployment.
Factual error: Near the beginning of the film before James McAvoy heads up to the house for the evening meal, he is seen looking up through a skylight when a Lancaster bomber slowly flies overhead. At the time it was was supposed to be 1935. The Lancaster bomber did not fly until the beginning of 1941. Can't be an Avro Manchester either, they only had two engines and first flew in 1939.
Factual error: Towards the end when the cavalry uncovers the American flag, it has 50 stars.
Visible crew/equipment: When the Muslim armies approach Brendan Gleason's castle there is a side shot of the Muslims army coming to a halt. You can see the marker stake with yellow tape at the top (used during production as a mark). (01:10:10)
Revealing mistake: Near the start of the film, when Lt. Harley is watching his love interest show off by doing gymnastics on the tree limbs, several times you can see the actual pole she is swinging on, not the tree limb. (00:08:50)
Revealing mistake: In the major helicopter scene when Ride of the Valkyries is played, the actual tape isn't going over the playing heads. (00:37:29)
Continuity mistake: When Tom Selleck rolls his plane upside down to dump the Afghan at several thousand feet altitude, you plainly see stationary tree tops at the bottom of the frame.
Factual error: Here's a big historical mistake. The character of German Admiral Lütjens is depicted overall in this film as a wild-eyed Nazi fanatic. In real life, he was distinctly anti-Nazi, vehemently protested the anti-Semitic actions of Hitler's regime, and was himself subject to intense Nazi scrutiny as he was a quarter Jewish and his wife was half Jewish. He was one of many German naval officers who fought only for their country, not Hitler.
Other mistake: Before the battle, the leader of the waterbenders says that he will have everyone extinguish as many sources of fire as possible. When the firebenders come up from the ground at the start of the battle, all of the torches lighting the city are lit.
Factual error: It is said in the film that Ice Cube's character works in an airport in Detroit. When the scene shows Ice Cube at work as a baggage handler, there are mountains in the background. There are no mountains in the Detroit area. (00:14:10)
Continuity mistake: During the middle of the film, a butler comes in and out of the Dictator's office several times repeatedly. The door is open and shows the corridor outside the office, casting the shadow of a window off-screen. The shadow changes from small to big bewteen shots.
Visible crew/equipment: The camera searches for Dora whilst Guido plays music through the open window. In her room, you can easily see a cable (from a microphone or a spotlight?) on the left side of the screen. (01:42:00)
Factual error: In the beginning of the movie William supposedly boards the train in Lincoln, Nebraska. All the vehicles in the train are from Europe and never rolled in the United States. (00:03:35)
Continuity mistake: When the main character goes to visit his friend that had been shot in Iraq, they're driving down a country road in a 2 door Dodge Challenger, but when inside the vehicle it's a Dodge Charger, which is a four door car.
Factual error: In the scene where the king attempts to seize the five members from Parliament, Cromwell makes a dramatic refusal to leave and proposes various "Laws" to prevent his arrest. Cromwell was not one of the five members whom the King tried to arrest and no law can come into force until it had been signed by the reigning Monarch anyway.
Suggested correction: It's more of a threat than a declaration.