- Billing Displacement: Peter Cushing got the top billing over Calvin Lockhart in the video releases.
- Executive Meddling:
- This is the reason for the Car Chase. It was inserted at the insistence of one of Amicus' executives who wanted a car chase sequence, so Paul Annett and screenwriter Michael Winder hastily came up with a "Jan tries to drive off in his Mercedes and Tom pursues him in his Land Rover" scene.
- This is also the reason for the "Werewolf Break," which was added against Annett's wishes by another producer, Milton Subotsky.
- Same Language Dub: Marlene Clark (who plays Caroline) was dubbed by Annie Ross.
- Similarly Named Works: There is also an unrelated novel named The Beast Must Die.
- Troubled Production: Surprisingly averted, despite this being Paul Annett's first feature film. Other than the mild cases of Executive Meddling, everything went swimmingly. The only real snafu was that the roast used for the two dinner scenes went bad due to the studio's on-site refrigerator breaking, and the crew was unable to get a second one in time to shoot the second dinner scene. So the entire cast had to just ignore the awful stink and pretend to eat the slices of meat they were serving themselves while filming.
- What Could Have Been:
- Robert Quarry and Shirley Bassey were originally stated to play Tom and Caroline Newcliffe.
- In the audio commentary for the DVD, Robert Annett laments having not had a copy of "There Shall Be No Darkness" to read before production began, as he thinks making Davina a witch would've added an interesting element (her equivalent in the short story, Doris, is a witch).
Trivia / The Beast Must Die