The alien jungle designed for this serial by Roger Murray-Leach was considered so successful that it was used for several years as an example of quality design by the BBC Educational Service.
This was Elisabeth Sladen's favourite story because it was the one where she and Tom Baker, and their characters, properly bonded in her opinion.
This was the first story to feature the Fourth Doctor behind the console of the TARDIS. The TARDIS console room had not been seen on-screen since Death to the Daleks: Part One (1974). A new TARDIS console makes its television debut in this story, although it was first used in Pyramids of Mars: Part One (1975) which was filmed before this. However, due to an oversight the TARDIS console room - as seen in this story and Pyramids of Mars - did not include a scanner screen.
This episode was budgeted a mere 3,000 pounds for materials and dressing, and 700 pounds for action props. That equates to approximately 37,300 US Dollars in 2017. In comparison, the average production cost for an episode of Doctor Who in 2015 was around 770,000 US Dollars.
This serial was released by the BBC on video cassette in the UK in January 1994.