Revealing mistake: When building the shelter, it takes both John and Don to lift the supposedly heavy panels; however when upright the panels bend easily when gripped. Obviously some sort of styrofoam/aluminium foil prop.
Lost in Space (1965)
1 revealing mistake in The Hungry Sea
Starring: Guy Williams, June Lockhart, Mark Goddard, Marta Kristen
Visit to a Hostile Planet - S3-E2
Continuity mistake: When the guy shoots the Robinson Robot it leaves a big bullet hole on the front. In the next shot we see the Robinson Robot turning around and the bullet hole is gone.
Robot: My micromechanism thanks you, my computer tapes thank you, and I thank you.
The Great Vegetable Rebellion - S3-E23
Trivia: Due to their uncontrollable laughter during filming of the infamous "Vegetable Rebellion" episode, Guy Williams and June Lockhart were written out of the next two episodes.