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.
Continuity mistake: When Jimmy and the rest of the kids are standing on the balcony, Jimmy asks Goddard to activate his binoscope so they can get a better view of the arena. Goddard then extends his eyes into tubes and raises them. However, in the next shot, his eyes are raised but not extended into tubes yet. They also take on a different shape than in the previous shot. (01:04:53)
Continuity mistake: During the show and tell scene, when Cindy finishes her presentation, she carries her model dinosaur skeleton back to her desk. However, the dinosaur skeleton is not seen at her desk, nor is it with her when the students leave after the dismissal bell.