Revealing mistakes: Before Dr. Forrester breaks his abacus apart, the sticks in it start to shake noticeably as he "calculates" on it.
Continuity: While attempting to remove the Hubble Space Telescope from the Satellite of Love's hull, Mike's face is very sweaty in every close shot - but bone dry in every interspersed long shot of him as he controls the "Manos" manipulator arms.
Continuity: Mike folds the newspaper twice.
Crew or equipment visible: Puppeteer Trace Beaulieu's hand is visible working Crow when Servo's Interociter is revealed. This is only viewable on the Widescreen version of the film.
Continuity: When Mike Nelson first enters the theater at "Movie Sign", he's wearing the shorts and college t-shirt he was exercising in. When he later exits the theater, he's wearing his normal blue jumpsuit.
Errors made by characters (possibly deliberate errors by the filmmakers): When Mike and the Bots are riffing their own credits, Crow's mouth barely moves for any of his lines.
Crew or equipment visible: During the opening sequence showing the "Satellite Of Love" orbiting the Earth, the clear support arms for the SOL model can be seen.