Continuity mistake: When Ford and Arthur are looking through the bins aboard the spaceship, the fourth bin's lid closes by itself when the camera angle changes.
Continuity mistake: When Arthur is aboard the spaceship, his hair style has changed from the style he had when he was in his house and the pub earlier in this episode.
Continuity mistake: Ford's hairstyle is noticeably both longer and curlier in this episode than in the previous one.
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.]
Other mistake: The instructions for the "manual improbability button" are written in English on an alien spaceship.
Revealing mistake: Right after we see the two suns of Magrathea, the screen fades to another scene. As the screen fades, pay close attention to the sun on the right. You will notice that the "sun" is actually a light bulb that turns off right as the screen changes shots.
Revealing mistake: The mice on the table are in slow motion. What's more, you see the same shots of them several times.
Audio problem: When Deep Thought is describing how he's going to create a new computer, he describes it as "a computer that can calculate the answer to the ultimate question." This is wrong: Deep Thought himself just did that. The new computer is supposed to calculate the question, not the answer.
Visible crew/equipment: When Zaphod says his first line "I certainly didn't survive.", you can see the person who plays his third arm standing behind him.
Chosen answer: That seems to be an error in the subtitling of the episode. What Marvin actually says is: "I may just be a menial robot, but I'm far too intelligent to expect to think of me for a moment... far too intelligent..."
Sierra1 ★