Continuity mistake: Nick's necklace is a string looped through a ring, but sometimes the string makes only one pass through the ring and sometimes two.
Continuity mistake: When Jimmy Neutron is giving birthday presents to his mum he pulls out a necklace and some earrings from a bag. His mum only takes the necklace from him but the earrings are no longer in his hand. (00:20:10)
Continuity mistake: In the opening sequence, Jimmy uses a long string from Carl's shirt to help launch the satellite. Jimmy then launches Carl from the rocket. That same morning, Jimmy finds Carl hanging from a tree, and his shirt is intact.
Continuity mistake: When Jimmy goes to check his experiments, there is a fish tank type thing and he then checks the invisible hamsters and the girl eating plant, but when he gets to the burping soda the fish tank thing is gone.