Revealing mistake: After the crew transport themselves out of the book depository to escape the FBI, the astronaut helmet is transported afterwards and the two FBI agents start shooting at the box the helmet was placed on. When the box is shot, there are no bullet holes left on it.
Continuity mistake: When the Nazi commander throws the crocodile at Ace, the yellow curtain is behind ace as he falls. In the next shot, the yellow curtain is in front of him. It is clear he did not fall through the curtain as it does not move as he hits the floor. (00:01:00)
Revealing mistake: When the simulant hits Able over the head with the steel bar, you can clearly see it bend. He hits him a second time a few moments later and it is straight again. (00:14:45)
Revealing mistake: When Kochanski is shot with the spear, the padding that gives the impression the spear is through her leg is visibly bulging in her trousers as ahe pulls on the rope. (00:26:50)
Revealing mistake: When the ship crashes into the snow planet, a wire can be seen attached to it as it crashes.
Factual error: When Kryten revives Lister with the defibrillator paddles, he places them on the clothing he is wearing. Defibrillator paddles need to be applied to bare skin for the electricity to get through. (00:27:35)
Revealing mistake: When Lee Harvey Oswald is preparing to shoot JFK on the fifth floor of the book depository, there is a shot of him from the side where he points his gun out of the window. To his left are a numerous boxes belonging to the book depository. Many of the boxes have "books" written on them, and some have hand written numbers on them. Later in the episode, the crew go back in time to send Oswald up to the sixth floor, but in the side view shot where he points his gun out of the window this time, the boxes are completely identical to the ones used on the fifth floor. The same set was likely reused.
Continuity mistake: When the crew are in the cockpit when Ace Rimmer is entering their dimension, Rimmer hopes that it is not him. When he says this, there is smoke around him, but this smoke was not there in the previous shot. (00:10:45)
Continuity mistake: At the start of the scene where the crew are giving Rimmer a funeral, Lister is shown clutching his "tie", and turns to Kryten, but in the next shot, he is suddenly looking up at the ceiling. (00:24:25)
Continuity mistake: When the crew meet the alternate dimension crew, both crews are standing side by side, but when the two Listers shake each other's hands, the Cat and Kryten from both crews have disappeared.
Continuity mistake: In the Aigburth Arms, when Frank hands the box with baby Lister to the barmaid, the barmaid takes the box placing her hand on top of the box, but in the next shot, her hand is suddenly on the side of the box.
Continuity mistake: When hologram Lister has finished explaining to the crew why he is dead, the crew are standing side by side, but when Lister asks what happened to Kochanski, Cat and Kryten have vanished.
Audio problem: During the munchkin song, near The End, one of the lines of the song is "then he just might come round for dinner" - however Rimmer mouths "he might just come round for dinner" instead - swapping the words "might" and "just" (00:26:00)
Continuity mistake: When Ace Rimmer releases the crocodile, it bites Captain Voorhese's head, and the two begin to fall when Ace removes Voorhese's parachute. When the crocodile lands on the ground a few minutes later, there is no sign of Voorhese. (00:02:15 - 00:04:25)
Answer: It's Queen Victoria, someone any Englishman would recognize, and needed no introduction.