Revealing mistake: When the Cybernetic ghost says "There's no way to stop it," he moves his head a bit and you can see part of his neck piece is missing.
Continuity mistake: At the start of the film the way Meatwad holds onto his guitar changes between shots.
Continuity mistake: When the Teens land in Africa their parachutes land on the ground. We see a shot of Africans and then back to the Teens. The parachutes have disappeared.
Continuity mistake: When Master Shake is performing "Nude Love," Carl's necklace disappears. It reappears, only to disappear again when the Insane-O-Flex explodes.
Revealing mistake: Meatwad and Shake get booted off the computer by Frylock so he can find instructions to the Insane-O-Flex. Watch the computer monitor. It rumbles, but the logo on it stays still.
Continuity mistake: When Frylock is watching New Jersey getting destroyed by the Insane-O-Flex, look for a building to the left through the Ferris Wheel. When Meatwad transforms into a building, the fires briefly stop, then turn on again.