Clive Barker had developed elaborate back-stories for the Cenobites in the first film, though their origins were never explored. In this film, he wanted to make sure that, at the very least, the audience understood that the Cenobites were once human, and that their own vices lead to their becoming demons. This element was meant to underline the story of Frank (Oliver Smith) and Julia (Clare Higgins) and their corruption by lust, with the latter intended to become the ultimate villain of the series. Pinhead, however, proved much more popular with audiences, and thus became the center point in further sequels.
An in-depth subplot detailing the origins of Pinhead (Doug Bradley) was scripted but deleted in preproduction due to last minute budget cuts. All that remains of this subplot is the film's prologue showing Capt. Spencer opening the box and transforming into Pinhead. Pinhead/Capt. Spencer's backstory was later explored in Hellraiser III: Hell on Earth (1992)
William Hope said that when his mother-in-law and nephew were in London, they asked if they could join him in one day of filming. Hope said yes, much for his surprise, because that particular day, they were filming the gruesome scene of the mattress. He says his mother-in-law was shocked, but his nephew loved the day.
The trivia items below may give away important plot points.
Julia (Claire Higgins) was originally supposed to rise from the mattress as the "queen of hell" at the end of the movie, the theory being that she would be the series' continuing character. Once "Hellraiser" opened, however, Pinhead proved to be the most popular character among the public.
The original script which featured Larry Cotton as a major character was essentially the same as the final film produced except that Larry WAS in the chamber with Frank, where they were attached to each other like Siamese twins until Frank attacks Kirsty at which point Larry cuts them apart and they begin to fight until Julia arrives. Later, Larry escapes with Tiffany and Kirsty from Hell and it was him, not Kirsty, that kills Julia, but he promptly has a heart attack and is ushered away when they return to the hospital. This segues into the notorious deleted scene with Pinhead in OR scrubs where he informs Kirsty that Larry will die in an imitation of a doctor. However, Larry returns at the end still alive and it is him, not Tiffany, that Kirsty leaves the hospital with.
When Channard is forced into the giant puzzle box and turned into a Cenobite, for a moment when he first enters the box his position in it is reminiscent of Francis Bacon's painting "Figure With Meat". The painting is the same one that's nearly slashed up by the Joker's henchman, Bob, in the art museum in Batman (1989).