Sorry for the long delay in replying. I missed this when you posted it.

At first glance there does not seem to be any difference in the 2 editions other than it was first published as a novella then later republished as a stand alone novel. The page length for both is the same as far as I can tell at around 185 pages -- which these days is right in the sweet-spot for a novella but in the early nineties would pass for a novel.

The novella was published in 1986 and was the basis for Hellraiser which came out in 87. The stand alone novel came out after the movie to take advantage of the film's popularity -- it's got Pin Head right on the cover. Here is where it gets interesting. It appears that the novel was updated to fit the changes made by Clive Barker for the film adaptation -- some name changes and the protagonist's love interest was changed to his daughter etc. Then the novel version was mined for the movie sequel, Hellraiser II.

We have 2 versions in the DB because of the changes made in the novel version and have listed Hellraiser as the film that came out of the original novella and Hellraiser II as the film that came from the modified novel version.

Thanks for the great question! I enjoyed doing the research.