Revealing mistake: At the point where someone gets a small bruise on the upper arm, the crew are all in a pile and thrashing about on the floor. There are 5 pairs of legs instead of 4. Arthur is in his pajamas, Zaphod is in orange trousers, Trillion is lying on top of Ford and Ford is too far away for them to be his legs. [The fifth pair of legs belong to the person playing zaphod's third arm - doesn't mean it's not a mistake, but that's where they come from.]
The Greatest American Hero (1) - S1-E1
Continuity mistake: In one scene, Ralph is in a phone booth desperately trying to make a phone call. Ralph is nervous and panicky. But when you look at his reflection on the phone, you can see a big relaxed smile on him. When it cuts back to him, he is still acting nervous and panicky.
Visible crew/equipment: When Miss Hawk is speaking to Edward by the well, the boom mic can be seen in the top right of the screen.
Continuity mistake: When Colt Seavers is chasing the villains in the golf cart, the camera equipment on the back of the cart keeps disappearing and re-appearing.