John Dies at the End is the film adaptation of the book of the same name. It was written for the screen and directed by Don Coscarelli, whom you might know from The Beastmaster, Phantasm and Bubba Ho Tep. It stars Chase Williamson and Rob Mayes, with a supporting performance by Paul Giamatti, who is also an Executive Producer.
Provides Examples Of:
Adaptation Distillation: How Dave gets the soy sauce forced onto him, and how he's found by "Morgan Freeman", are both shortened and changed. Likewise, The Stinger about John and Dave walking away from becoming another dimension's saviors, the appearance of the wig monsters, and what Marconi is are changed. A few characters and the trip to Las Vegas, as well as the cloning sub-plot, are removed.
Adaptation Dye-Job: Amy is repeatedly described as a redhead in the books, while she's a brunette in the film. Most likely a consequence of being fused with Jennifer Lopez.
Adaptational Attractiveness: In the book, David repeatedly describes himself as pudgy and out of shape, while in the film he has a healthy build, aside from a very slight double chin. John in the film is also much more chiseled than his lifestyle in the book would allow.
Marconi in the book is a former globetrotting explorer and reverend turned to psychic medium, and while he's popular with the psychic crowd, he's not any bigger than any other 'psychic' in Las Vegas. In the film, not only is he massively popular, he also displays karate skills, walks around with a entourage of beautiful ladies, manages to get his hands on a city-destroying weapon made of C4 and LSD that was made in the Cold War, and engineers the entire plan to defeat the villains.
Bark Lee, going from possibly an angel to very smart dog, due to ingesting the soy sauce, sacrifices himself to destroy Korrok.
Affably Evil: The Large Man is very polite and seems to genuinely believe that David and John should feel honored to become one with Korrok.
Artifact Title: As with the book, John only "dies" partway through the story and gets better pretty quickly.
Art Shift: The educational film about Korrok's world breaks into a cartoon to portray a scene of mass destruction. It's obviously a budget-saving maneuver (the original scene depicted a miles-long trench of men, women, and children being maimed by Korrok's spiders), but the Large Man justifies it by saying that it will be easier for David and John to watch.
Asshole Victim: The little we see of Justin White before he gets taken over by Shitload is him being an asshole to Amy at the party].
Badass Mustache: So badass, it rips itself off its owner's upper lip and flaps around the room like a rabid bat.
Batter Up: John gives David a baseball bat coated with Old Testament bible pages, with nails driven through the end.
The Cameo: Angus Scrimm, the Big Bad of Coscarelli's Phantasm series, appears as the priest David calls about an exorcism.
Casanova Wannabe: Fred Chu, who, in the novel, is a simple stoner slacker, tries hitting on Amy in the film and toasts to "all the kisses he's snatched, and vice versa."
Demoted to Extra: Amy. While the heroes spend a good portion of the book looking for her, protecting her, and getting to know her, in the film she only becomes relevant to the plot in a single scene.
Everybody Must Get Stoned: This turns out to be the reason most of the people who took the Soy Sauce got murdered - they all gathered (except John and Dave) to go get stoned. Instead, they get gruesomely torn apart, or, in the case of Justin, infected.
Gorn: Notably not as present as the book, but still there: the horrifying pictures Appleton gives Dave during his interrogation that used to be the other people who took the soy sauce, and Appleton's eyes exploding.
Pragmatic Adaptation: Amy is given a prosthetic hand for most of her screentime to make her easier to film without special effects.
Running Gag: Severed limbs. In addition to Amy's missing hand, John's band "Three Arm Sally" has a logo consisting of three severed arms, and the phantom cop who tries to strangle David has his arm ripped out of his socket - which continues to strangle David.