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)
Factual error: In at least one scene, near the end of the film, metallic alloy dental fillings can be seen inside King Leonidas' mouth. Fillings of this type were not used until the 7th century A.D.
Factual error: When the Marines strip off and run into the sea in the final scene, Doc takes off a pair of white socks that would be more appropriate for a final at Wimbledon. Not only are they white rather than khaki, they are virtually spotlessly clean which would be impossible after a week of fighting on the black sands of Iwo Jima.
Factual error: When American Cosair fighter planes strafe the Japanese soldiers with their machine guns, only two columns of bullets are seen striking the ground. These planes had six machine guns; there should be six columns.
Factual error: Midway through the film, the IRA flying column successfully ambushes a motorised British patrol. Immediately afterwards, when the column's survivors are milling about on the roadway, one IRA man is shown to be armed with a German Mauser Kar 98k bolt action rifle. This is historically incorrect, as this weapon did not go into production until after Hitler's assumption of power in the 1930's - at least thirteen years after the events depicted in the film.
Factual error: The movie takes place in 1868, and every guy and his dog are wielding cartridge conversion Army, Navy, and even what appears to be Walker colts. Unfortunately, such conversions were not performed until 1869, after Smith and Wesson's rights to the Rollin White patent expired.
Factual error: During the movie the Germans are more then once using halftracks of the type sonderkraftfahrzeug 251, which originally were only allowed to be used by panzerdivisionen (armored divisions), and at the moment the movie is supposed to take place, there were no panzerdivisionen in Holland.
Factual error: As Christian Bale's Skyraider releases rockets, at first they drop like bombs. In real life, rockets shoot away instantly, at an almost straight line from the launching plane, never falling like bombs.
Factual error: Sharpe follows a wagonload of powder kegs into the Western Gatehouse, then down a corridor lit with torches, to the end of the corridor where Indians were tying together quickmatch, once again by torchlight. With the propensity for powder kegs to leak, even an Indian subadar would use closed lanterns.