Halloween III is not a bad movie per se, as it parodies cliches and has fun with its plot's silliness, but it ultimately can't be called good because of its poor building of atmosphere, timing of scares, and anticlimactic moments throughout.
Here we have a masterpiece of characterization. The film belongs not to Chandler, not even to Altman, but to Brackett, the screenwriter, and the amazing characters she created and the actors who play them. Just watch how each character has a special personality. How actors aren't used just as models or vehicles, but as distinct human beings.