Audio problem: When Bunny (Ramon) is, as Zorro, spelling out "Zorro" on the wall with his whip, the number of whiplash sounds does not match the number of marks in the wall.
Audio problem: When Mel Tillis and Terry Bradshaw are trying to "re-tune" their race car, when Bradshaw tells Tillis to "hit it one more time", the car makes the distinct starting sound of an older Chrysler when the car was a Chevrolet. Also, how does Tillis starts the car? He has one hand on the steering wheel and his other hand is on the doorframe.
Audio problem: When Comicus is announced in Caesar's court, the trumpeters play "Hooray for Hollywood". Notice that the music starts before they get their instruments to their mouths.
Audio problem: When Kevin and his crew of thieving little people land in the Middle Ages, Randall informs Kevin that they made all of what's surrounding them, trees, shrubs, bushes etc. Kevin's reply is "Phew, that's not bad" He says this without opening his mouth. This was looped into the film later on.
Audio problem: During the "Shock Treatment" musical sequence, look carefully at Dr. Nation McKinley's (Patricia Quinn) lips at the end of her solo speaking part. She mouths words to the song, even though the only voice you hear is Dr. Cosmo McKinley's (Richard O'Brien).
Audio problem: When Burt Young is dining with Iris he laughs/chuckles at one point yet his mouth never opens.