Continuity mistake: When Lister and the Cat are talking to the original Rimmer in the cinema, the new Rimmer enters and argues with the original. The original Rimmer makes hand puppets, while the new Rimmer sits at the front. When Lister does the ippy-dippy, the Rimmers have swapped places. The new Rimmer says that he was there first, without complaint from the original. (00:23:30)
Revealing mistake: When Lister goes to Rimmer's room the second time, the door opens before Lister hits the switch.
Continuity mistake: Lister and Rimmer's bunk room looks exactly the same in the flashback scenes during this series as it does in the present time. In the first series it looked completely different, so surely the look should have changed slightly for the flashback scenes?
Other mistake: The shots of Blue Midget driving back to Red Dwarf that are shown from behind are visibly the exact same shots used each time. This is evident as the driving movements of Blue Midget, its position in the frame, and Red Dwarf's position in the background are all identical each time.
Visible crew/equipment: When the crew are in their sleeping quarters, and Rimmer is talking to the others, a blue boom mic can be seen hovering over his head (you can see this if you watch the dvd on your pc, as some tv's can cut off the edge of the picture) (00:03:10)
Continuity mistake: When Holly interrupts Rimmer learning Esperanto saying "The menu looks interesting", he appears on the TV screen, with his chin blocked by the edge of the frame. The shot then cuts to a view of the screen, and his entire face is suddenly fully in the frame. (00:05:00)
Continuity mistake: When Lister is getting ready, he pulls his trousers off the table, causing the boot on the table to wobble. In the next shot, the boot is entirely still. (00:10:35)
Continuity mistake: When Lister is questioning how they can remake Casablanca, he is holding the video tape, but in the next shot, the tape has disappeared from his hand and is touching the control panel. (00:04:40)
Revealing mistake: When Holly is talking about his chess game, you can see his black clothing to the left of his chest, revealing he's hiding a body, and isn't just a computer generated floating head. (00:06:30)
Revealing mistake: In the observation dome, the borders of the blue screen used to project the image of space behind Lister and Rimmer can be seen around the dome. (00:09:55)
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