- Billing Displacement: Venetia Stevens is only billed with 'And Introducing' despite Nan being the central character for the first half hour anyway.
- Executive Meddling: The American release cuts out three lines in which characters invoke the name of Lucifer - despite being plot-relevant - because the censors found them offensive.
- Fake American: All the cast were made up of British actors playing American characters. The exception is Venetia Stevenson, who plays Nan. Although English born, she grew up in California.
- Follow the Leader:
- The film bears several similarities to Psycho - involving the protagonist being murdered at the halfway mark, with her sibling then investigating her disappearance. Bonus points for both featuring creepy hotels prominently, as well as a climax involving the villainess's withered face. But this one was actually in production first, and both were coincidentally released the same year.
- During the 60s there would be several films dealing with devil worship and black magic - such as The Witches (1966), The Devil Rides Out, Eye of the Devil and The Wicker Man (1973).
- What Could Have Been:
- The story was intended as a pilot for a horror series with Boris Karloff starring. It was never made and the script instead became a standalone film.
- Following on from the above, the pilot would have ended with Nan's sudden death. The second half of the film added the plot of Dick and Bill investigating her disappearance.
- You Look Familiar: If you look at the opening scene, two old women appear again when Nan visits the town.
Trivia / City of the Dead