"Police Academy II: Their First Assignment" isn't much of a movie, but whaddaya expect, "Citizen Kane"? Like its predecessor, it combines the usual dumb stuff with an edge of comic inventiveness that brings it beyond gross-out farce. If much doesn't work, much does; there are a solid half-dozen belly laughs here -- how many comedies today can boast as much?

The outcasts from the police academy return as full-fledged cops. They're called in to help a hapless precinct, run by Commandant Lassard's brother Pete (a sedated Howard Hesseman), that is besieged by a criminal gang. Lt. Mauser (Art Metrano) wants them to fail so that he can step into Lassard's shoes. So Mahoney (Steve Guttenberg), incorrigible prankster that he is, puts Mauser in his place with practical jokes.

As in "Police Academy," the real fun doesn't grow out of the situation -- the story is simply scaffolding for the shtick. They're not movies so much as variety shows featuring talented young comics. Michael Winslow, reprising his role of Dr. Monsignor Larvelle Jones, can sound like anything from a slurping straw to a flat tire to a police siren (he calls himself a "vocal visionist"). "Police Academy II" includes a brilliant set piece in which Winslow, confronting two thugs, performs a dead-accurate parody of a Bruce Lee movie, complete with dubbing.

Stand-up comedian Bob "The Bobcat" Goldthwait makes the gang leader Zed into the nuttiest psychopath in years; he seems to be trying to wriggle out of his own face, and his voice is a jumble of insane roars and spoiled whininess. And Peter Van Norden brings such joy to the role of the overeater Vinnie Schtulman that even the broadest humor works. When he picks up a bowl of cereal and scolds his cat, "How many times do I have to tell you -- the litter box, the litter box!" and proceeds to eat nevertheless, he spoons away with such gusto that it's a howl.

Much of the humor of "Police Academy II" is pretty routine -- there are even Krazy Glue pranks, and an annoying, repetitive resort to gay-baiting. Guttenberg is a genial straight man, but when he's asked to do more than that, he waxes sitcommy -- he has no wildness to draw on. The movie could use more of the priceless George Gaynes, whose Commandant Lassard was the high point of the first movie. But longtime "Happy Days" director Jerry Paris keeps it moving along. The best thing about "Police Academy II" is that it doesn't feel like a sequel -- with its crazy freshness, it never acknowledges that it's just exploiting the success of another picture. Police Academy II: Their First Assignment, at area theaters, is rated PG-13 and contains nudity, sexual themes and some profanity.