The Hitchhiker's Guide to the Galaxy (1981)

Episode 3 - S1-E3

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.]

Episode 4 - S1-E4

Revealing mistake: The mice on the table are in slow motion. What's more, you see the same shots of them several times.

Episode 1 - S1-E1

Continuity mistake: In the Guide entry on the Babel Fish, the teletype text that displays the words spoken by the guide stops after the word 'anything', but the voice of the book speaks a further line.

Moose ★

Trivia: Douglas Adams makes several cameo appearences in the series. A drinker in the pub in part one, the man walking into the sea and a member of the Cirius Cybernetics marketing division in part two.

Josman

Slartibartfast: I'd much rather be happy than right, any day.
Arthur Dent: And are you?
Slartibartfast: No. That's where it all breaks down, of course.

Arthur Dent: You know, I've always had this feeling there was some greater purpose.
Slartibartfast: No, that's just ordinary paranoia. Everybody in the Universe has that.
Arthur Dent: Well if everyone has it, then perhaps it means something.

Episode 6 - S1-E6

Question: When Marvin is left behind in the Disaster Area ship as the others teleport away, he says, "I'm so intelligent I've probably got time to go through the five." before he is cut off. Is there anything in the books or rest of the series which suggests what we was about to say?

Moose ★