Continuity mistake: When Sikes is put into the headpiece and Claw has the power turned up full force the chin strap is first around Sikes's chin, then it isn't, then it is.
Continuity mistake: When evil Gadget and good Gadget are on the ground fighting you can see the car behind evil Gadget. They then show both from the side and the car isn't there but when they go to good Gadget it's behind him again.
Continuity mistake: In the beginning of the movie when the bus has no brakes, the dog is on a leash. When Gadget grabs the dog and throws him and catches him, there is no leash.
Continuity mistake: When Evil Gadget jumps out of the chief's office, he is seen falling forward, but in the next shot is seen falling backward just before he lands on the sidewalk.