Continuity mistake: Shaggy and Scooby stop to play a game of pool. When Scooby looks up and notices the ape head trophy has vanished, he has 4 of the balls by him, including the 6 ball. It cuts over to Shaggy, and he has the exact same set of balls next to him.
Audio problem: Shaggy and Scooby are walking around trying to find the Ape Man to lure him into the trap. There is a sound and Shaggy says "What's that noise?" It cuts to Scooby who is following him who says "RI ron't row." But his mouth does not move at all when he says this.
Continuity mistake: The Ape Man puts on a mask of Scooby and pretends to be a reflection. As he is mimicking Scooby's movements, he places his hand to Scooby's and his nails are sticking up. It cuts to a different angle and his hand is in a slightly different position, and his nails vanish.
Continuity mistake: Scooby finds a half eaten hamburger in a plate on the floor. When the camera cuts further back to show Shaggy, the plate has moved on the floor, as noted by the lines between boards and the placement of the plate and the spider web on the wall.
Continuity mistake: When Shaggy makes the joke about living without a smart Ape Man, he's lying on his stomach with his legs in the air behind him. His feet are apart as he relaxes. Then suddenly in the same shot, they just jump close together and then slowly spread back apart.
Continuity mistake: After Candy and the stunt man quit the movie, Mr. Maxwell says he has to withdraw his job offer to the gang as it's too dangerous. As the gang is shown, Scooby is sitting in front of Shaggy and Fred. It cuts to a close up of him as he gets excited about this, and suddenly Fred and Shaggy have vanished.
Continuity mistake: The Ape Man breaks the rope bridge that Scooby is on and it begins to fall. But by the Ape Man, the stakes holding the broken ropes are still in the ground at his feet. Scooby falls down and lands on a root, which bounces him back up where he punches the Ape Man. The stakes and broken rope have vanished.
Continuity mistake: The camera pans over the filming set and stops on the gang with Mr. Maxwell. There is a van behind them with the Ape Man movie poster on the side. The vinyl piece on the side of the van goes behind the poster and is lined up directly with the orange letters saying "EPI-CENTER FILM COMPANY." It then cuts to a close up of the poster and suddenly it has moved up on the vinyl and become smaller, lined up with the underside of "LOCATION No.2"