Visible crew/equipment: When the Red Dwarf crew are talking about who Legion is (after Lister has poured his bucksfizz), Kryten then says, "Could our very presence here have inadvertently awoken him?" As he says this, at the left side of the screen the end of a camera lens pulls away.
Other mistake: At the start of "Backwards", there is a spoof "Star Wars" type caption, which spools up the screen very quickly. Too quickly to be read in fact...which may explain why few people have noticed that the last line of the caption "And now the Story Continuums..." is written TWICE
Other mistake: Kryten places Rimmer's light bee on the floor, then begins the process of reinitialising him. As the process finishes and Rimmer looks at Lister (who looks away), the light bee, which should be hovering within his torso projecting his image, is still visible on the floor between his feet.
Continuity mistake: In the captain's office, the words 'Medical bay' have been painted on the wall. This was near the end of the episode and can be seen over Rimmer's shoulder while they are talking in the drive room. The set was obviously doubled with the medical bay, as the captain's office is not used in this episode.