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.
Revealing mistake: When the farmer is going to shoot the sign the bank put up, you can very well see the mark where the hole is going to appear.
Continuity mistake: There's a scene where Audrey Hepburn's husband Sam is leaving their apartment. Standing on the pavement outside he hails a cab, which pulls up through a (quite sizeable) puddle, splashing him with water. Opposite him on the other side of the road are parked two cars and the villains' Volkswagen van. There's a quick cut-away exchange of "pleasantries" between Sam and the cabby before it drives off. The next shot has the villain (Richard Crenna) emerging from the van, crossing the street, and making for the door to their apartment, only all of a sudden the puddle has disappeared, as have the two cars which were parked behind the Volkswagen van.
Continuity mistake: During a session in class when they were discussing marriage etc, Potter and Denham can be seen in the background leaning in their chairs against the wall. The discussion then involves them and the Teacher played by Sidney Poitier. In the scenes that follow it shows them leaning on their desk when the pair of them are talking to the teacher, and when the teacher is talking it shows them in their original posture with their chairs still tilting.
Continuity mistake: At the beginning, right after the opening credits, Old Timer picks up a gold rock. When he first picks it up, we see a close up shot of his hand holding it only an inch or so above the ground. The very next shot a second later, from the side, shows his hand holding the gold instantly a foot or so above where it was before.
Revealing mistake: When the brown Vanden-plas hits the skip you can see that the cars engine has been removed also the moment of impact is shown twice.