Other mistake: When Chester is taking Jacko's pipe, Nelson gets up out of his seat. When they show Jacko really really mad, you can look in the background and Nelson is sitting down. When they show him again he is out of his seat.
Visible crew/equipment: When Jesse and Chester pull up next to Fabio, the shot changes to a frontal shot of Fabio and his girlfriend. A microphone is visible in the car's windshield reflection just left above Fabio's head. (00:29:40)
Continuity mistake: In the beginning of the movie, the pan of the house shows the lava lamp on. While the camera is on Jesse, the lamp is off, and when it leaves him, the lamp is on again.
Continuity mistake: When Tommy is in the pizzeria talking to his girlfriend (Kristy Swanson) he takes a bite out of his pizza. After she leaves, the outer space vixens come in and after they leave he goes to take another bite and the slice is whole again.
Revealing mistake: When the "dudes" are taking out a load of bin bags, you can see through the lighter coloured ones that they are actually filled with polystyrene chips (the packing kind) rather than any litter.
Continuity mistake: When Jesse and Chester meet the outer space chicks for the first time one of them takes Jesse's Popsicle, swallows it and pulls the stick slowly out of her mouth. At this point it is still red like the Popsicle. We see Chester and Jesse look at her and in the next shot the chick pulls out the whole stick but now it is completely clean, no more red dye on it.
Continuity mistake: When the boys are taking the garbage out of their girlfriends' house, the bags they're carrying change size and colour from shot to shot.
Revealing mistake: When Chester completes the Rubik's cube and it transforms into the continuum transfunctioner, it descends into his hands but if you look closely, you can see that he takes his hands away from it and it magically floats just above his hands.
Continuity mistake: At the ostrich place belonging to Pierre, they climb the perimeter wall and jump from the tree. As they jump, they are side by side and as they fall on the ground in the next shot, they are the other way round. They don't seem to swap sides as they fall however.
Continuity mistake: When Jesse and Chester are taking out the trash, Chester takes off his left shoe and sock. In the next shot, it is his right foot which has no shoe or sock.
Continuity mistake: Right before they get picked up by the followers of Zoltan there's a little girl playing hopscotch who disappears and then reappears in the next clip.
Audio problem: When the duo enter the Kitty Kat Club, a dancer shouts ''Look everyone. It's Mr. Jesse and Mr. Chester.'' It sounds like she is talking from a loudspeaker, when in fact, she is just talking.
Continuity mistake: When the main character orders fast food at the drive in, he first has his arm outside the car, then the camera angle changes, and the arm is inside, and so on...
Factual error: The average speed of an African Ostrich is 31mph, not 27mph as noted in the film.
Continuity mistake: When Jesse smashes the Chinese drive-thru speaker, you see him break a chopstick off and throw it on the ground. As they drive away, the speaker has 2 chopsticks again.
