Best action movie mistakes of 1969
Factual error: While Bridger is watching the film of the Mafia boss following Beckerman he signals for the film to be stopped so he can look at the close up shot of the man. He is watching a 16mm film shown through a bog standard projector - stop a film like that for more than two seconds without closing down the projector shutter (this doesn't happen - if it did the screen would darken instantly) and it will melt and catch fire. This doesn't happen.
Continuity mistake: It is 1940. Two pilots come out of a house - one of them has just lost his wife and family in the London Blitz, the other is an RAF Squadron Leader. The door they come out of has a modern electric bell push - a post 1965 version, white rectangular box with a round button.
Continuity mistake: Sykes is shot in the right leg, in the thigh area, by the bounty hunters. We see the blood clearly on it when he sits on a rock and holds his leg. Later, when he returns to Aquaverde where he meets Robert Ryan, we see as he sits on his horse that his left leg is bandaged.
Revealing mistake: When the Remagen bridge is bombed, it is obvious that the bomber planes shown have been taken from several shots (possibly also from an earlier film) and the shots were superimposed. Also, the bombers appear transparent, and the background sky's color is unnaturally strong, too.
Revealing mistake: Captain Beckman is in the tower shooting at a small German plane that is attacking the castle. He is told to aim for the engine but when he does and shoots it down its not the engine that smokes, its both the wheels that are smoking from some very obvious smoke tubes attached to the fixed landing gear.