Continuity mistake: When Leonidas, and presumably all the other Spartans, use their spears to clear their shields of arrows after the arrow shower from Persian archers, the tips of the arrows are still visibly left on all their shields. In the next shot, when the Spartans regroup for the Persian cavalry charge, the arrow tips are gone. (Granted, this is a highly stylized movie based on a comic book, but that does not change the fact that this is a continuity error.)
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.
Visible crew/equipment: When Dieter steals the rifles from the hut and approaches the other prisoners before their attack on the kitchen, a crew member (wearing a cap) can be seen moving from the right of the screen to the left with a camera or some other equipment. (01:19:35)
Visible crew/equipment: During the scene where Seagal is locked in the room and creates his knife gun, Seagal walks over and smashes a wall. As the camera pans around from right to left, the camera goes past him and continues to the left showing a crew member facing him.
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: 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.