Plot hole: If everything goes backwards, shouldn't Kryten and Rimmer have got fired, done their job and then got hired? Rimmer & Kryten discovered that everything was backwards in the cafe earlier in the episode. At the club they did their act and then got fired. Put this 'forwards' and it becomes wrong.
Visible crew/equipment: When talkie Toaster says, 'I toast, therefore I am.', you can see the legs of a crew member moving in the reflection of the toaster. (00:04:40 - 00:11:50)
Continuity mistake: Watch the cat priest's black hand. It starts off normal, then it turns crusty and white. Just before he dies, his hand is normal again. (00:25:55)
Continuity mistake: When the crew are wheeling the Cat in the corridors of Red Dwarf, Kryten is holding onto the Cat's hand. In the next shot he is pushing the stretcher. (00:23:00)
Continuity mistake: Lister's rolling pin is dirty with flour when Christine walks in, but when Lister turns around, it's clean. Then it's dirty two seconds later, and then disappears completely after Lister drops the bowl. (00:26:12)
Visible crew/equipment: Just after Lister hits the toaster, a pair of legs can be seen moving in it's reflection a moment before the scene ends. (00:11:30)
Visible crew/equipment: Just before Starbug crashes and Kryten says they will have sandwiches for lunch, a boom mic can briefly be seen above his head. (00:09:45)
Out Of Time - S6-E6
Revealing mistake: When the crew wake up from stasis, there is a model shot of Starbug flying towards the epicentre. You can see the legs of Starbug partially disappear as it gets closer to the ship. (00:12:45)
Continuity mistake: During Ace Rimmer's funeral, the blow up doll is not visible earlier in the scene next to the Cat, but then appears from nowhere. (00:24:50 - 00:25:40)
Rimmerworld - S6-E5
Continuity mistake: During the hold-up scene with the Simulant, in the close-up of her speaking, her face is in darkness. The camera cuts away to Rimmer running for the escape pod, and then back to the Simulant, who is now well lit by a pair of overhead lights. (00:12:10)
Visible crew/equipment: When Lister is speaking to Kochanski and realises it is actually Rimmer, Kochanski says "it's Kochanski's body, it's Kochanski's voice" and a red boom mic is visible at the top of the screen. (00:27:45)
Stasis Leak - S2-E4
Continuity mistake: When Lister walks through the Stasis Leak for the first time, his hands are up by his face and his locks are in front of his shoulders. In the next shot from the mirror, his arms are lowered and his locks are only over his right shoulder. (00:09:30)
Continuity mistake: When Kochanski puts the cat in the disintegrator, it changes the way it's facing between shots and again when she takes it out. (00:11:19)
Visible crew/equipment: A boom mic shadow appears on Lister's head just after he opens the door with the severed hand. (00:19:20)
Answer: The cello is a large four-stringed instrument, which, when it is played, stands vertically on the floor between the player's legs (assuming they are seated). If it is to grow as large as the other instuments mentioned will, it would require a rather unseemly lack of femininity to be able to encompass it with the legs.
Rooster of Doom