Revealing mistake: Near the end of the film, there is a football game played between the rival MASH units. Although the game is supposed to be taking place in a remote location of Korea in 1951, late model 1960's automobiles can be seen driving on a nearby highway as the game progresses. This gave away the fact that the football scenes were shot at a university in Southern California.
Factual error: In the scene where the king attempts to seize the five members from Parliament, Cromwell makes a dramatic refusal to leave and proposes various "Laws" to prevent his arrest. Cromwell was not one of the five members whom the King tried to arrest and no law can come into force until it had been signed by the reigning Monarch anyway.
Continuity mistake: About 3/4 through the film, which is supposedly set in the 1900s, there's an exterior shot of Jenny Agutter (as Roberta) talking to William Mervyn (as "the old gentleman"). Over Mervyn's shoulder can be seen a white delivery van driving rather fast along a road on the other side of the valley from where the filming took place (this is very obvious in the wide-screen version but less noticeable in the pan-and-scan TV version).
Continuity mistake: Burt Lancaster is sitting in his car at the end, and he asks the tower if he can listen to the radio traffic for the incoming plane that's landing. The tower replies "Sure, it's on frequency 117.1". Burt then tunes the dial on his receiver to 171, not 117. 170 is blatantly written under the dial in bold type.
Continuity mistake: When Tawes goes upstairs into the room where Alma is sitting on the bed, they hug then sit on the bed, and kiss. As they kiss, Tawes places his hand on her left shoulder. Then when it cuts to a closeup, his hand is missing.
Continuity mistake: In the scene where Jack Nicholson finds the piano on the back of the moving truck, he uncovers it and tosses the tarp on the side of the truck. Over the next few shots, the tarp disappears and then reappears draped over the side of the truck. As well, the shots of Billy Green Bush taken from outside the vehicle show his hands gesticulating wildly, while the shots from inside the vehicle, from over his right shoulder, show his right hand calmly positioned on the upper right part of the wheel. This scene also contains a magically appearing chair. When Jack first finds the piano, he has to lean over to play, but a few shots later, he is seated comfortably on a straight-backed kitchen chair. (00:19:10)
Visible crew/equipment: In the scene where Luke has stolen the Jaguar from the old rich guy, there is a part where Luke drives the Jag up the wall of the tunnel and lands it on top of a truck. It is obvious that the car that goes up the wall isn't even real, it looks more like a Matchbox or Hotwheels car....
Continuity mistake: In the scene at the hockey game where Oliver talks to Jenny while he's in the penalty box, he wears number 7. When the shot cuts to the action on the ice during this conversation, number 7 is in the game sliding on his stomach, and then back in the penalty box talking to Jenny. (00:04:10)HuskyMiller