Truthfully, the production isn't so bad (no worse than most King adaptations) and the direction is rather passable. The bug, like in most bad films, is the script.
With such a strong cast and good production values, this should have been a great film.
But somehow the story bogs down at the beginning, more interested in the terrible management of an old mill than the giant monster in the basement. The story makes a play at being true to the source while making a statement but by the last 30 minutes it suddenly remembers that it's a horror movie and tries to stuff the denouement and everything else into a few rushed scenes. The monster, which was actually quite good, doesn't even get time to breathe.
Brad Dourif does his best to save the movie, playing a creepy exterminator with a Jeffery Combs style mania (if the two of them were ever in a movie, the world would explode from the awesome).
But in the end this film had everything, from a giant bat to a good cast, and it still sucked.
