Franchise Zombie: The first four films have an actual continuity and contribute things to the series' Myth Arc like the Labyrinth, the origin of Pinhead, the LeMarchand bloodline, and the death of Pinhead. Afterwards, creator Clive Barker cut ties with the franchise and every subsequent film is a Dolled-Up Installment that drastically changes the role of the Cenobites from neutral extradimensional pain seekers to demonic punishers of the wicked with Reality Warping abilities and contributes nothing to the Hellraiser universe aside from throwaway Continuity Nods.
The Other Darrin: Starting with Revelations, Pinhead stopped being played by Doug Bradley: In said film he is physically portrayed by Stephan Smith Collins while being voiced by Fred Tatasciore, while in Judgment Pinhead is portrayed by Paul T. Taylor.
Roughly half the cast were dubbed with American accents (despite the film being explicitly set in London) at New World's insistence, and unfortunately the undubbed cut has yet to see a release of any kind.
Several scenes were cut down to avoid an X rating, and haven't been edited back into the film, although some have appeared as DVD extras.
Playing Against Type: Played with. Andrew Robinson, who's best known for playing the Scorpio killer in Dirty Harry, plays an average loving family man named Larry Cotton. Larry is oblivious to the fact that his wife is cheating on him with a demonic apparition of his brother and killing people. It becomes subverted when Frank kills him and takes his skin for disguise, making Andrew play Frank by proxy.
Andrew Robinson thought "Jesus wept" sounded so much cooler than the scripted line "Fuck you". Clive Barker agreed, and the line made it into the movie. Seeing as it's become one of the most iconic lines in horror, it seems they were both right.
As was the line "Enough of this cat and mouse shit."
Troubled Production: The production had No Budget and series creator Clive Barker had to find creative methods of dealing with issues. Shooting in a house with only a single camera to spare, Barker was forced to rely on overhead and zoom shots due to shooting constraints and limited areas to move in. Several of the effects (including Larry's blood being sucked into the floor and Frank's rebirth) were either reshot due to looking unconvincing, or required additional funding from New Line Cinema to complete because of cost overruns. Barker himself has said that the dodgy nature of the FX can be traced to him completing the majority of the work over a single weekend (while getting drunk with a Greek animator) after filming wrapped. The original soundtrack by industrial band Coil was also thrown out, with Barker commenting that it made "my bowels churn", and replaced with an orchestral score by Christopher Young. Barker also had to deal with the MPAA to get the rating down from an X to an R. Despite the hardships, the film was a major success, earning more than $14 million against a $1 million budget.
The music for the film was originally done by Coil (they were hired by Clive Barker after he listened to one of their albums and nearly got sick due to how brutal their music was) but the studio ended up rejecting it due to its content. Their score ended up getting released separately and Christopher Young did the score that ended up in the film (which launched his career as a composer).
A video game adaptation was planned for the Nintendo Entertainment System by none other than Color Dreams, creator of many low-quality unlicensed games for the system. It was to be the first of their games to use what they called a "Super Cartridge" that would've had four additional megabytes of RAM, sprite manipulation, and fully animated backgrounds, among other things. However, due to the production costs and the expected higher price than a standard NES game, the game was canceled.
The film is set in England (hence the obvious London locations), but the studio, New World thought the film would be more marketable if it featured more American accents. So many of the English actors (including Sean Chapman, Oliver Parker and others) were dubbed with American accents, resulting in a Where the Hell Is Springfield? situation.
Lance Henriksen was offered the role of Frank by New World Pictures, but he turned it down, fearing that if successful, he would have to appear in a series of sequels, which he wasn't keen on. He would later go on appear in Hellraiser: Hellworld.