Continuity: How could Ned shoot Kenny by accident when he was unable to shoot Scuzzlebutt because he had run out of ammo?

Continuity: When Jimbo asks the children if they want beer, the campfire stays still for two shots.

Plot hole: Scuzzlebutt is trapped by a river of lava but is able to accept thanks from the Mayor. To do this he would had to have crossed a river of lava.

Continuity: When Ned, Jimbo and Kenny are out on the fishing boat they have a rocket attached to a rack. After firing the rocket the rack still remains, but in the next shot when they head for shore the rack is gone.

Continuity: The clock behind the geologist shows different times between scenes.

Deliberate "mistake": When the boys are hunting in the forest, then they start to crawl after the rabbit, however, the background behind them is static as if they were crawling in place.