Corrected entry: Towards the end of the movie where American soldiers were trying to remove the tops of the air vents, a German sniper has his cross-hairs on a soldier's forehead. When the sniper shoots, the next view is of the American putting his hands up to his face. The American was shot in the forehead which would negate any conscious after the fact movements on his part.
Corrected entry: Prior to the attack on the Chateau, one of the team climbs a telegraph pole to cut the phone lines. To support himself he uses a brown and yellow webbing belt of the type introduced to British telephone engineers in about 1968. During WW2 a leather belt would certainly have been used.
Corrected entry: As the convicts are building their training camp, Posy is shown with blueprints and a clipboard on which he is writing something. Later, when Posy comes out from talking with the psychologist, it is firmly established that Posy is illiterate: "The captain thinks he can teach me letters." How can he be reading blueprints and lists?
Corrected entry: Bizarrely, this film is partially based upon a real incident - the ending of which is somewhat different to that in this film. Twelve US soldiers on death row or serving long prison terms were selected to undertake a highly dangerous mission behind enemy lines in France in 1944. One of the US Army officers responsible for them was Ernest Hemingway, another was - of all people. - Russ "Supervixens" Meyer. All twelve were intensively trained and then transferred to a transit camp near Caen to be prepared for their final mission. As soon as they landed on French soil, all twelve deserted.
Corrected entry: When Donald Sutherland is pretending to be an incognito General inspecting the troops (as the camera pans down the lines of solders to inspect) a helicopter can be seen clearly in the distance over the soldier's heads. While helicopters were air tested during WWII, it is highly unlikely to see one in service.
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.
Col. Everett Dasher Breed: Reisman! Some people may consider you a first-class officer. But as far as I'm concerned, you're a disorganized, undisciplined clown. I'm gonna' make it my business to run you out of this Army.
Major John Reisman: I owe you an apology, colonel. I always thought that you were a cold, unimaginative, tight-lipped officer. But you're really quite emotional, aren't you?
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.