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.
Factual error: In one scene a parked car is sitting along the street - it is a '68 Chevy, it has sidelights. Yet the film is set in 1962.
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.
Continuity mistake: During the fight in the hotel, Dawn Brakes pulls down the Mayor's trousers with both hands. Dawn then puts her left hand to her mouth in shock. In the next scene, she is seen putting her right hand to her mouth and her left hand is on the Mayor's trousers.
Audio problem: In the shop scene at Ginsberg and Cohen's, when Miles replies, "Something simple," he never opens his mouth to do so.
Revealing mistake: At the beginning of the film, Stan reverses the bus into the manager's car. While the manager is under the bonnet looking at the engine, causing it to fall on him, you can see a rod with padding on it to stop the bonnet from hitting the manager. It is gone in the next scene.
Other mistake: Dunnaway fires a warning shot next to her father to encourage him to leave the property. In the sequence just before he leaves she fires one shot and there are two dirt eruptions near his legs.
Continuity mistake: Victor Pivert is in full road rage mode as he is waiting at a road stop after skipping most of the line speeding through the emergency lane. As he bickers with his French compatriot, he hammers his horn initially with the right hand, then after a pause he starts hitting it with his left hand in a side view, which turns instantly into his right hand at the cut. (00:08:30)Sammo
Revealing mistake: At the beginning of the movie, the coked-up sailor is shooting from a rooftop and screaming various racial slurs. Despite that, there's a big crowd building. When he shouts "Come and get me, honkies!" you can see people running way before he pulls out of the gun again and shoots. Not only that; some of the extras are just enjoying themselves and not keeping a straight face, far from being scared. (00:01:00)Sammo