The film holds the distinction of being one of the few slasher films in horror film history to receive an MPAA PG rating, as the PG-13 rating wouldn't exist for five more years.
Director David Schmoeller was startled when the film received an MPAA PG rating despite its disturbing subject matter and what he perceived as graphic violence. Schmoeller stated in an interview with TerrorTrap.com that he felt the film would have been more commercially successful had it received an R rating.
The mannequin who gives the female lead something to drink is actually director David Schmoeller's then-wife. The mannequin originally had 2 lines, but Schmoeller had them edited out during post-production. She never forgave him for that.
The script originally called for nudity, but director David Schmoeller said he was too bashful and embarrassed to bring it up with Tanya Roberts and the other actresses during casting. When they got to the lake scene, Schmoeller finally asked them if they'd be willing. The collective answer was no, even though Robin Sherwood had been nude in her first film The Love Butcher (1975). She would later go nude in her last role in Death Wish II (1982). Tanya Robert's would finally go topless that same year in The Beastmaster (1982) and fully nude in Sheena, Queen of the Jungle (1984).
Irwin Yablans reportedly hated Pino Donaggio's score for the film, as Yablans wanted another synthesized score in the same tradition as John Carpenter's Halloween (1978).