Frank Larrabee and his band performed their song "California Lady" in the film after they were coerced by the filmmakers. The film crew and the band were both staying at the Ramada Inn in Albuquerque where the performance footage was shot.
The original cut contained more graphic horror makeup. The camp massacre scene in particular had more gruesome shots of victims. However, this footage was heavily edited for television. The television cut of the film is the only one available.
Co-writer Bill Finger is probably best known for his work in the early days of DC Comics, where he co-created the Green Lantern, Batman, Robin, Commissioner Gordon, and most of the key members of Batman's rogue gallery, including his most popular adversary, Joker.
The film was shot in September 1972, then sat on the shelf for 4 years, looking for a distributor. In the end, it went straight to television.
Leigh Drake said in an interview that production was so problematic she thought the film had never been released. Years later, her stepmother told her she'd seen a DVD of the film, and was surprised to hear that it had been distributed after all.