I just completed watching all 8 Hellraiser flicks.
I had seen bits and pieces of a few of them (which I now recognize as 3 & 4).
It so awesomely fits into the Horror Movie franchise cliches of being ridiculously horrible by the end of their run, deteriorating bit by bit with each installment.
Here's the breakdown:
Part I: A pretty solid horror movie. Good sci-fi supernatural story that doesn't involve Pinhead much at all. He was no more central of a character than the other three Cenobites (gatekeepers of hell), except he had a couple more lines than the other one that could talk. The Cenobites were not a central part of the story anyway.
Part II: Brought back pretty much all of the central characters. Stuck to the original story, and expanded on it. Went more into explaining things like the Cenobites and the puzzle box. Solid sequel as far as horror sequels go.
Part III: The series begins heading downhill. The characters from the first two movies are abandoned, except Pinhead. It then becomes about him. They contradict the canon of the first two movies to make Pinhead a typical late-80's/early-90's Hollywood movie monster a'la Jason & Freddy who can recruit other Cenobites, which are now just basically zombies with super powers.
Part IV: Takes place in Space 400 years in the future. And partly in the present. And partly 400 years in the past. Only four parts in and it's already this ridiculous.
Part V: A murder mystery thriller with a bit of a supernatural twist. Kind of like a poor man's Se7en. Are you sure this is supposed to be a Hellraiser movie? Quite a departure for the series, but I guess on some level it's kind of cool that they abandoned the blood and guts and made it about Pinhead psychologically torturing someone.
Part VI: Basically the exact same movie as part 5, making it even more predictable. This one was made in 2002. Just enough time for Halloween H20 to come out and have been successful and them to try to steal an element that worked for it. Jamie Lee Curtis came back for that one. The main protagonist teenage girl also returned for the late Nightmare On Elm Street movie, New Nightmare. This must have been why the girl from the first two Hellraiser movies wanted to come back for this one. Clearly her part being the same girl from the first two movies was an element thrown in at the last minute. It is completely unnecessary to the plot.
Part VII: Unbelievably, has even less to do with the Hellraiser series than the last couple of movies. It was clearly written as a movie to stand on its own, and the studio that owns Hellraiser said "Hey, we'll buy it if you put Pinhead in there somehow and call it Hellraiser 7."
Part VIII: Hilariously bad acting. Like worse than most porn. Ridiculous and stupid story. Ridiculous and stupid lines. This tries to be totally hip and deals with online gaming. A bunch of teenagers are obsessed with a Hellraiser based online game, and through the game they get invited to some big party, where guess what, Pinhead kills everyone one by one. All the kids are self-aware of all of the elements from the Hellraiser series, seemingly because of the video game, not the movies. It's so god-awful it's funnybad.
Just thought I'd share. I knew each one would be worse than the one before it, yet I kept watching all 16 hours worth, and frankly, would have been disappointed if one of them had actually been better than the previous one.