One thing that you notice after watching a lot of Stephen King movies is that King is very good at making really cheesy things sound scary on the page, but those same things often come off as silly when presented in a movie. Graveyard Shift is a great example of that, as well as the stretching that filmmakers have to perform when making a 17-page short story into a feature film. Graveyard Shift is about killer rats, which are really creepy when you imagine them, but look mostly harmless in this movie as they just kind of sit there and wiggle their noses. The rats infest a decrepit mill in small-town Maine (naturally), a place run by a demented foreman who demeans (and sexually harasses) his employees. He bribes an inspector to keep the mill open despite numerous code violations, and thus the downtrodden workers are stuck working in abominable conditions.
Stephen Macht plays the foreman with evil intensity and one of the strangest accents I've ever heard in a movie. I guess it's supposed to be a Maine accent, but no one else in the movie even bothers with the regional tone of voice, and Macht throws as much Eastern Europe, Ireland and Jamaica into the mix as he does Maine. It's thoroughly distracting and kind of funny, and sort of makes up for the fact that David Andrews is beyond bland as the hero, a noble drifter who's mocked by his co-workers for having a bunch of fancy book-learnin'. Both of them are upstaged by the always entertaining Brad Dourif as the overzealous exterminator hired to get rid of the rats; he has one great monologue about the use of rats in the Vietnam War before exiting the movie way too early.
The whole climax takes place in some kind of underground catacomb below the mill, where the rats give way to a seriously silly-looking giant rat-like monster (which really looks more like a bat). By that point, any minimal amount of suspense is long gone, and the characters haven't distinguished themselves well enough for us to care whether they live or die. The thin concept is stretched to the breaking point, and what's left to implication on the page becomes laughably explicit onscreen.
How far to Castle Rock: Female mill worker Jane mentions that she grew up there.