Originally, The Doctor's last line was "I know, I'll take you to Blackpool". This would have lead into the planned first serial of Season 23, The Nightmare Fair. When the series was put on hiatus, the line was shortened.
This was the final serial to use Peter Howell's arrangement of the "Doctor Who Theme" that had been introduced in 1980.
This is the first Dalek story to explicitly show a Dalek that is capable of levitation. Though this ability was first implied in "The Chase", the Daleks' groundedness (and inability to climb stairs) was a recurring source of mockery among fans and even served as the butt of a joke in Destiny of the Daleks: Episode One (1979). From this story until Journey's End (2008), all televised appearances of the Daleks would feature them levitating.
There's a lovely three shot at 1:00:53 of Colin Spaull, Trevor Cooper, and Clive Swift, all who also have rolls in Doctor Who (2005). And to top it off, this story is directed by Graeme Harper who is the only one who directed both in Classic Who and New Who.
The complete footage of the Doctor finishing his line "...Blackpool" at the end of the episode (a scene that was cut, being replaced by a freeze-frame in the finished programme) now no longer exists.