Revealing mistake: As Machine Gun Joe runs slowly runs over a fisherman in a small brook, he stops and "peels out" on his head. You can see a film crewman in the driver's seat doing the actual carnage.
Continuity mistake: Jonathan explains how to deal with a biker, demonstrating on Blue who's sat on his bike close to the rail. Yet when he's talking to the new guy (Toughie)Blues bike is in the middle of the track and when Toughie comes around the track to attack Jonathan it is back in its original position.
Continuity mistake: Chaney wraps his first fight up very quickly. As he does, the jacket in James Coburn's arms changes position between shots. (00:10:45)