Revealing mistake: When the tank/truck driven by Marvin is crossing the stone bridge at the end, they are met by a small German gun vehicle, which they run off of the bridge. The camera angle changes to below the bridge and you see the German vehicle fall from the side of the bridge into the water below. If you look at the bridge material that shatters you can see pieces of wood and hollow areas where obviously it's not real stone. (02:25:00 - 02:30:00)Japan-Games
Continuity mistake: As the Dirty Dozen ready for the wargames, they are in a truck passing and saluting a line of American light tanks in closeup. Immediately after turning left into a circular driveway and stopping, in a long shot the tanks have quickly turned into a long line of Army trucks. There was no time for the tank convoy to drive off and have a convoy of trucks enter the scene.
Trivia: We never actually see Posey (Clint Walker) die on film. We know where he is during the mission and we only saw his partner Bravos get shot but not Posey. I always have this funny feeling that he may have survived and the surviving members (Lee Marvin, Charles Bronson, and Richard Jaeckel) of the Dozen forgot about him.