Continuity mistake: In George's memorial service, the extras are totally different in the shots from George's point of view to the shots from the back of the room. Look for the woman with brunette hair and orange overalls - she's there in the forward shots but missing in the reverses. The chairs, tables, props, costumes and character placements are all completely discontinuous.
Continuity mistake: When Lister and Rimmer see Cat just after Holly explains how he evolved, Rimmer runs at Cat screaming before he passes through him and we hear a crash off screen to indicate Rimmer has just run in to something. He is a hologram and is not solid, so no sound should be heard. [The original version did not have this mistake. The sound effect was added for the now defunct Remastered series.]
Continuity mistake: At the start of the 'Welcome Back George McIntyre' reception scene, Lister, Chen and Selby are throwing things at Rimmer, then Rimmer looks around. In the next shot, Lister and Chen are looking round to their left, Selby is stabbing between his fingers, Rimmer is now looking straight forwards and Petersen has appeared from nowhere.
Other mistake: At the start of Rimmer's exam, the invigilator orders the students to "turn over their papers and start". Rimmer reads one side of the paper, then turns it over to read another question. The back of the paper should have been blank as otherwise there would be no point asking the students to keep the papers face down before reading the questions.
Continuity mistake: When Rimmer and Lister leave their sleeping quarters, there are two pictures on the wall between the door and the window and a canister on the wall beside the beds. When they are next in the room the items are gone, and at the end of the episode they have all returned.
Continuity mistake: When Lister goes into stasis, Todd Hunter turns the wheel on the door to lock Lister in. In the next scene when Lister awakes from stasis, he just pushes the door open without turning the wheel to unlock it. Even if we are to assume that Holly would automatically open the door, the wheel should still turn to unlock the mechanism.