Dreamcatcher isn't Stephen King's best book, and it's far from the best screenplay produced by either Lawrence Kasden or William Goldman. It's mishmash, but there is something in it to scare the bejeebers out of just about everyone, including yuckiness, gore, creepiness, intense peril, and good, and old-fashioned jump-out-at-you surprises. The four main actors are all exceptionally appealing, and the art direction and cinematography are top-notch. The film's weakest aspect is Kurtz's secret operation. Even the masterful Freeman can't quite make that character work, and the attempt to create a parallel between the peril created by the outside force and the peril from within does not work, either.
While parts of the plot are lackluster, as I watched this movie the audience reaction sounded like they were on a roller-coaster ride, a good sign in a scary movie. It's not a classic like Carrie or The Shining, but it is a nicely done scarefest, and achieves its modest ambitions.