Best comedy movie mistakes of 1973
Continuity mistake: At one point D'Artagnan reaches the Duke of Buckingham, who is on a hunt. He has just killed a stag and his hands are covered in blood. D'Artagnan rides up and offers him a note from Queen Anne. He wipes his palms with a cloth before he takes the note, but his hands are still covered with blood up to and above the wrists. When he reads the note, he and D'Artagnan take off on foot for his castle where they go into a private room behind the walls. Suddenly it is apparent that his hands are perfectly clean right down to his scrubbed fingernails and, without explanation, the plot-heavy sequence continues.
Plot hole: A vital plot line, obviously, is that Doyle wants to kill the con men who fleeced his runner of the numbers money. He has Luther killed and turns his best men (and women) onto Johnny Hooker, almost killing him, too. What about the third conman, Kid Erie? He is an essential part of the con, as much a part of it as Luther and Hooker. During the setup - just before they fleece him - the numbers runner watches Kid Erie running away. He looks at him, Hooker and Luther in turn. Even if he couldn't identify him he would still be able to inform Doyle that there were three rather than two con men involved. Even so, Kid Erie comes and goes as he pleases. Doyle doesn't have anyone looking for him; he doesn't even mention him in conversation, and in fact consistently refers to two - not three - con men. He makes it clear that he would have to kill his best friend if he even found out about the con, yet he lets one of the central participants go scot free. It doesn't make any sense at all.
Continuity mistake: When Jack goes to the surgery to take his pleasure with the nurse, he chalks on the blackboard on the door that the nurse will be unavailable for 30 minutes. When Blakey arrives, the 30 minutes note has gone from the blackboard. But when Blakey opens the door with his passkey, the 30 minutes note has re-appeared on the door.