This marks the first time the TARDIS was hit with an arrow. The other two times were The Shakespeare Code (2007) and Robot of Sherwood (2014). All three times see the Doctor played by Scottish actors - Sylvester McCoy, David Tennant, Peter Capaldi.
The climax builds on a plot thread begun in Remembrance of the Daleks: Part Four (1988). Lady Peinforte accuses The Doctor of being more than an ordinary Time Lord, and he stoically evades Ace's questions on the matter. Originally this thread was building up to the revelation that The Doctor is the reincarnation of the original founding Time Lord, but the matter was dropped with the original series' cancellation the next year, and never revisited in any other Doctor Who series.
This was the final Cybermen story of the original series. They returned in Rise of the Cybermen (2006) and The Age of Steel (2006).
For the music played by Richard and the others in the final scene, Keff McCulloch originally created a rendition of the series' main theme.