After first meeting the cat and returning to the teaching room, all the piles of crew members' ashes have disappeared from the desks.
When Lister and Rimmer argue in the drive room, Lister stands up and walks across the floor. When he says, "You're a hologram, so what?" he is suddenly sitting down again.
When Lister says sarcastically says "No, it's a chicken", he looks at his cigarette, then at Rimmer. Then he's suddenly looking at it again as it cuts to a two shot as Rimmer responds by telling him he's on report again.
Lister's hand disappears just a second before he puts it through Rimmer.
In the Cat's first scene, the wall with the 'Storage Locker' sign wobbles after he moves past it (the cameraman or another crew member probably bumps into it).
In the Remastered version of the episode, Robert Bathurst's name is misspelled 'Robert Bathhurst' in the closing credits.
Edge of a crew member's body is visible in the window when Lister tells the door to lock after Rimmer leaves for the exam.
When Lister asks Todhunter if going into stasis will hurt, a camera's shadow can be seen moving out of shot on the edge of the stasis booth door.
Boom mic briefly visible in top left hand corner then is lifted away when everyone stands for the cutting of the cake at McIntyre's welcome back reception.
Lister spilling the milk when he pours it in a bowl for his cat Frankenstein is actually accidental, since he doesn't spill it in outtakes where the cat runs away before he can get hold of it. But the milk spillage befits Lister's natural sloppiness.
As Lister walks into the bunk room, Rimmer pretends to be studying instead of copying test answers onto his body. He says, "...the py-thyrus theorum..." when he should have said, "...Pythagoras theorem...". Likely this was an error made by Chris Barrie rather than the character or writing.