Book: One of Stephen King's most popular novels, Pet Sematary came out in 1983. It relates the story of doctor Louis Creed and his family that faces a young son's death - a son Louis later revives at an ancient Indian burial ground.
Movie: Also titled Pet Sematary, and came out in 1989. Stephen King wrote the screenplay himself; the director of the movie was Mary Lambert. Starring Dale Midkiff and Denise Crosby.
Plot differences: The basic plot is the exact same as in the book. However, minor differences include the omission of Norma Crandall and her death, which is replaced with the suicide of babysitter Missy Dandrige, and more appearances by the ghost of Victor Pascow.
Character differences: Norma Crandall, Jud's wife, is completely omitted from the movie. Steve Masterton, a friend of Louis', has a reduced role. Missy Dandrige, who is only mentioned in passing in the novel, has a wider role and a completely different, hypochondriac personality.
Author opinion: Stephen King was probably happy with this, since he wrote it himself. He was tired of seeing his films adapted by others, and wanted to have a say in the matter.
Stephen King cannot write movie scripts, end of story. I haven't seen one TV movie, miniseries or feature film written by King that was any good. He's good at writing horror novels; Pet Sematary is one of his best books, and the concept of an unnatural child coming back from the dead is carried out well in the novel. However, he completely butchers his own concept in the movie.
Firstly, the dead speak in the novel. They say horrifying things about living people, telling them their sins and the bad things others think of them. Gage, the dead little boy, tells Jud Crandall that his wife cheated on him and laughed at him with all of his friends. This is unnatural and disgusting coming from a child, and it makes Gage scary. But what does he do in the movie? He talks in a childish voice, asks people to come play with him, grimaces with a knife in his hand. Zelda and Victor Pascow are at least scary in the movie, but Gage is just childish.
From the Wikipedia entry:
In addition, the movie glosses over the concept of the Wendigo in the forest, and completely skips over the implication that there is a singular, specific intelligence which guides the resurrected creatures and speaks through them.
Now, the idea of a specific intelligence behind the evil is much scarier than what happens in the movie. Jud Crandall relates the story of young Billy, who was resurrected by his father, but like Gage, he is much scarier in the book than in the movie. In the book, he speaks terrible things to people and knows all about them. In the movie, he shouts, "Love death! Hate living!" Ehh?
Secondly, the omission of Norma Crandall is very weird. Her death in the book gives a feel of natural death, dying from old age, as opposed to Gage's unexpected and terrifying death. King doesn't seem to realize that this is necessary to ground the story somewhat in the reality of death.
Thirdly, the dialogue is so cheesy. It's very difficult to buy a horror movie where the dialogue constantly takes your focus away from "oo, creepy" and back to "hee, kitschy". The scenes in the book have been transformed into unbelievably corny movie moments. The beginning is a good example. I'm going to quote my own recap of the movie:
Ellie runs off somewhere, and Rachel and Louis walk up to the house. "So...?" says Louis cornily, expecting a positive response, even if Louis in the book felt nervous and anxious about Rachel's response. I think Dale Midkiff is trying to portray "nervous and anxious", but comes up with "hey, look what I got you, don't you just love it?" Ridiculous soap opera music swells up as Rachel declares, "It's gorgeous!!" with the overdramatic tone usually reserved for messages like "I'm pregnant!" They hug and Louis laughs.
I assure you I'm not exaggerating here. It really is that bad. In the book, Louis is so tired of his family that he's contemplating just taking off without them and driving into the sunset all by himself. But in the movie, it's all "Look what I got you honey". I don't know why King chose to write the movie like this, but it's very difficult to buy.
The fourth glaring problem has nothing to do with King or his script. The acting is just really bad. Dale Midkiff is horrible as Louis Creed, a role that would demand some depth from an actor. You need to embrace not only joy and "family man" qualities, but also grief, fear, and being more or less possessed by an evil force that wants you to revive your loved ones. Dale Midkiff gives us *blank stare* through most of it. That doesn't cut it. Fred Gwynne is good as Jud Crandall, but everyone else pretty much hams their way through it. There's the scene of Gage's death, which should be tragic - but what does Dale Midkiff do? He shouts "NNOOOOOOOOO!!!" in the corniest, longest possible way. And they show still pictures during it. Of Gage as a baby. What the fuck was that? Was it Stephen King or Mary Lambert that decided this was a good idea? It totally ruins the tragedy of the moment. The subsequent grief is fast-forwarded over, it seems, and we jump straight to the horror part. That also takes away some of the power of the story.
I did find the film scary at times. The horror scenes mostly still work, and Zelda is really terrifying, as she should be. However, with some of the deeper levels of the book taken away, some of the horror is also lost. The film is helplessly 80's, helplessly time-stamped and kitschy, and very difficult to take seriously. Which is a shame, because I do think it's a good book. Sadly, there was also a low-quality sequel with different characters, directed by Mary Lambert, but this time written by Richard Outten. I haven't seen the sequel, but it has a 3.9 rating on imdb.com (the first movie has 6.1), which says a lot.
I'm intrigued about the new version someone's making for next year. The details are in imdb pro, which I'm not willing to pay for, but it's there for those of you with a membership. Let's hope they got it right this time!