- Acting for Two: The main cast play their regular selves and their alternate universe counterparts.
- Creator's Favorite Episode: This is Chris Barrie's favorite episode, because it gave him the opportunity to play both Ace Rimmer and Arnold Judas Rimmer.
- Deleted Scene:
- Extended model shots of Rimmer's childhood home on Io, including the Rimmer house which was not seen in the episode. Only a wider shot of the whole colony, and the gardens of the Rimmer family home, are seen in the episode. However in the model shots on the DVD the house can be seen - which was seemingly very modular, and resembling grain silos.
- Ace Rimmer's scene with Padre was originally longer, talking about how Ace had helped little orphan boy Tommy pull through after an operation. The extended dialogue also says that Ace donated all his money to helping the boy.
- Mellie also had an extended scene, asking Ace to bring cherries as well as maple syrup to their tryst, and breaking the fourth wall to say "what a guy".
- Blue-screen work was not completed on Ace's farewell scene on Mimas, which continued a running gag as Padre smells maple syrup on Mellie, and also includes Bongo and Spanners musing on how Ace will encounter another Arnold Rimmer and become fantastic friends and an exceptional team with his counterpart.
- A half dozen additional lines of dialogue and jokes, cut for time.
- The original ending to the episode whereby Rimmer with the help of the skutters tries to drop a sack of kippers on Ace, but they fall on him instead, was removed when the writers believed it didn't work on either comedic or logical levels (they would just fall through him). The kippers, which should have fallen straight through the hologram Rimmer, were intended to halt in freeze-frame. In the aired episode, Ace merely shrugs at the still-suspended kippers before walking off.
- Playing Against Type: Ace was specifically created so Chris Barrie could play someone who wasn't a git. Ace is literally everything that Arnold Rimmer isn't.
- Throw It In!: Holly fainting at Ace's good looks was not scripted and was Hattie Hayridge's idea.
- Wag the Director: The episode came about after Chris Barrie begged the writers to let him play someone who wasn't a git (he was also appearing in The Brittas Empire at the time).
- What Could Have Been: Originally, the Cat's parallel dimension counterpart was to be a slovenly janitor. However, the BBC ordered the writers to change this to the ship's chaplain due to concerns that the original intention would appear racist.
Trivia / Red Dwarf Season IV Dimension Jump