The phone number the killer calls for the bowling alley is 976-3845, which is 976-EVIL (1988), another 80s slasher movie.
Most of the gore effects were shot in a separate studio because the filmmakers didn't want to get fake blood all over the primary bowling alley location.
The film was the subject of much scrutiny for its frequent use of the f-word, which is spoken 500+ times.
Nicholson initially submitted the film to the MPAA but released it unrated after he was told 20+ minutes of footage would have to be removed to avoid an NC-17-rating.
The producers of this film agreed to base their promotional campaign after the 1980 cult classic Maniac (1980).