A notable deletion from the storyline was that those under WOTAN's thrall were originally intended to be discernible because their hands would take on a skeletal aspect, forcing characters like Dodo and Professor Brett to wear gloves to hide this mark.
Anneke Wills makes her first appearance as companion Polly. This was also the name of her daughter (b. 1963).
This is the only serial to use a different opening title sequence from the usual sequence, a special title sequence that looks like a computer printout that was made especially for this series.
The first appearance of Ben and Polly.
The Doctor makes a remark about an uneasy feeling he has when the Daleks are around. This turned out to be unintentional foreshadowing, as the first two episodes of "Evil of the Daleks" take place on the same day in a different part of London.