I don't like to criticize independent labor-of-love productions, but this is just not a good documentary -- unless you're interested in hearing a lot of people talk about what a genius they think Clive Barker is.
I've no doubt Barker is a major creative talent, and Hellraiser is a great horror movie, but it provides next to nothing about the making of the movie, the creation of the story, how it came to life, etc. I mean, apart from "This is a monumental film, Clive is a genius."
There's also almost no actual footage from the film, only occasional glimpses. Mostly it's one middle-aged (the movie is several decades old, after all) person after another talking about how much of a genius Barker is and how amazing it is that they were able to know him.
The film-makers start to delve into how Hellraiser fit in with the other horror movies of the era but it's all so superficial and shallow, and really it seems like the argument for why Hellraiser was so different from the other movies at the time is because it was just *so* different from the other movies at the time. The whole thing feels like a circular argument, which always leads back "I mean... a genius! The man is a genius!"
And even then, they don't even go into *why* he's a genius. People keep talking about how brilliant his paintings are, but then the movie barely shows them. People talk about amazing his books are, and yet I came out of the film not knowing the title of a single one of his books. The whole thing is just so superficial and frivolous.
And of course, Barker himself isn't in it. And also, if you're going to recycle that same, tired Stephen King "I've seen the future of horror" quote, then maybe you should actually interview Stephen King and find out why he said it, what made him think that, how was Barker different from the 'past' of horror, etc. But, nope. Almost all of the talking heads are people who haven't done much apart from Hellraiser.
There's a very good documentary to be made about Hellraiser, but this isn't it. Again, I get no pleasure from criticizing this movie, but this is the perspective of one person who watched it.
Post-script -- Wait, one of the other reviews here calls this a 7 hour documentary. Either he is mistaken or I saw only part of it or I'm confused or.... something. Anyway, what I saw dealt only with Hellraiser and Clive Barker, for what it's worth.