Continuity mistake: Arnie enters the parking lot driving on two wheels crying "Woooa." The close shots show him with one hand on the wheel and the other outside on the window; but on the wide shots, with the stunt, both hands are inside and his mouth closed but still the cry is heard. This mistake goes on every time angle changes.
Revealing mistake: While Julius is talking to the man in front of the lingerie store on Hollywood Blvd, when the man's partner rides up on a motorcycle and tries to snatch the suitcase, we can see the stunt wire carabiner attached to the back of his jacket as he flies off. (00:12:30)
Visible crew/equipment: When Julius enters the supermarket parking lot, in the long shot we can see the stunt ramp used to lift the driver's side of the car, to go into ski mode. In this and following long shots of the stunt, we can also see the window roll cage bar directly behind the front windshield (the obvious stunt driver grips the roll bar with his left hand and steers with his right hand), as well as the top of the seat supports behind the front headrests. (00:30:55)
Chosen answer: Although I wouldn't call one a bad guy, Professor Werner is the the one who raised Julius, and would remain a friend because of this bond. Mary Ann (the twins' mother) however, was told that Julius died at birth and was never told about Vincent. She blames Professor Traven for this (probably since he's the only one around to yell at). Vincent on the other hand was never told his mother died during childbirth and he grew up thinking his mother abandoned him. Until Julius showed up, he never knew he was part of an experiment and he had no knowledge of either doctors and probably no feelings regarding either of them.
Bishop73