Continuity mistake: When Richard Pryor and Gene Wilder are sitting on the park bench, the level and configuration of ice cream in the cones they're eating changes noticeably from shot to shot. (00:14:00)
Continuity mistake: When Dave falls from the hood of the car, the stuntman lands in a completely different position to that of Gene Wilder one shot later. (01:00:05)
Continuity mistake: Towards the end of the movie Dave takes Walley's jacket and uses it to help them slide down a cable. Before they slid down, Dave tells Walley to hold on, and Walley asks if they're going to be above the ground. Dave tells him no, and off they go. However, Dave is deaf, and reads lips, and Walley is standing behind him when he asks the question. So how did Dave read his lips if he wasn't looking at him?
Continuity mistake: Wally and Dave exit the swamp after pushing the police car in. Look at Wally's legs; you can see a pair of Wellington boots underneath his trousers.
Continuity mistake: There is a scene with Richard Pryor crouched in a corner being shot at by bad guys. A statue behind him is hit and shattered. In the next shot, it's standing there like nothing ever happened.
Continuity mistake: When Wally is whistling to lure the dogs away from the greenhouse, Kevin Spacey steps on his fingers to stop him. In that shot, you see that Spacey has the gun by his side. But in the next shot when you see his face, he's already got the gun raised.
Continuity mistake: After escaping from the police station, they go into a building and break a wooden door to come out of the other side. When they first break the door, the broken section is only inches away from Richard Pryor. Gene Wilder says to watch out for it. When Richard Pryor moves it, it's slightly further away than it was before.