I watched John Dies At the End on Netflix last night after finishing the novel a day or two ago.
While I had hoped for a Fight Club type movie that surpasses the source material what I got is a movie that represented some of the scenes in the book quite well in the first half but then rushed to get to a conclusion in the second half, again with some scenes represented verbatim from the book but a greater chunk excised.
I was even more disappointed to realize that the movie was directed by Don Coscarelli who did Phantasm back in the day. I don't know that Phantasm has aged particularly well but when I first saw it, it blew me away! And watching the movie I could see how David Wong's book was a literary version of Phantasm, yet wholly original at the same time.
And that is the failing of the movie, other than cramming a whole bunch of stuff that will probably leave people who haven't read the book completely mystified, is where it is true to the novel it fails to be wholly original and where it is wholly original it betrays the novel.
If you are a horror-comedy fan and haven't read the book and decide to give the movie a go, let me know what you think. I think the movie is worth watching if you are a genre fan and have Netflix. It has a few very nice set pieces and the first 15-30 minutes are very well done.