Continuity mistake: When Penny is strapped to the cart, Inspector Gadget frees her and they both run away from the cart. The cart then explodes and Inspector Gadget is propelled forward. The Gadgetmobile pulls up and Inspector Gadget lands on the bonnet from a position directly above, which would be impossible if he was going forward.
Other mistake: When Claw steals a whole bunch of gold, there seems to be a lot in there. First: How did he get so much gold in there with so little time? They seemed to have been throwing around the gold coins and stuff not to have enough time to do that. Second: Later in the movie you get an above look while they are trying to escape Inspector Gadget, there is less gold in the truck than there was earlier.