You can't be sure what to make of Identity for its first hour: Director James Mangold's initial foray into the horror genre plays so much like a joke it's almost impossible to tell whether he's making you laugh on purpose or because, well, he's director James Mangold, maker of the dopey Kate & Leopold and the dour Cop Land, and merely bumping into chuckles accidentally. Much of the movie plays like a gross-out version of Agatha Christie's Ten Little Indians, in which a bunch of seemingly unrelated people are picked off, one by one, by an unseen killer at a Nevada motel. It's so much of an homage that one of the would-be victims, a young bride played by Clea DuVall, can't help but ask the dwindling group if they remember "that movie where ten strangers are stranded on an island" and begin to die (though which version would be hard to say, since there have been several variations since 1945).

Clearly, much of the audience at a recent screening didn't find it terribly amusing; a man, sitting behind a colleague and me laughing ourselves blind, shushed us and insisted, "This ain't a comedy." He thought he was supposed to be scared, because such are the powers of persuasion when it comes to convention; an abandoned motel drenched in sheets of rain and buckets of blood surely conjures something terrifying, doesn't it?

Not in this case, not really, because Identity is terribly funny -- if not an outright comedy or a yuk-yucky camp parody like Scream or I Know What You Did Last Summer, then certainly a wry, mordant and close-to-brilliant commentary on films in which people misbehave and suffer gruesome, outlandish deaths (you know, baseball bats down throats, heads lopped off and deposited in oversize clothes dryers...that sort of thing). For some 60 minutes, Mangold and writer Michael Cooney so overinflate the genre and its excesses that they completely obliterate the Horror Movie; it explodes like a head that's been run over by a truck, which, more or less, also happens here.

Columbia TriStar is marketing the movie all wrong. Its trailers suggest a haunted-motel thriller with movie stars who appear to be slumming it, among them John Cusack as a cop-turned-limo driver who keeps tattered Sartre in the front seat, Ray Liotta as a cop schlepping a con (Jake Busey, who's all teeth), Amanda Peet as a hooker with a heart of citrus (she dreams of planting an orange grove), John C. McGinley as a nebbish with a dinged-up wife and a quiet stepson. They at first appear to be archetypes, because that's precisely what they are: Cusack grimly mopes about in the muck, looking for the killer; Peet tramps around in short shorts, licking whipped cream off a man's chest when first we see her; McGinley, so brilliantly manic on Scrubs, changes a flat and tends to his injured wife with anal-retentive intensity; DuVall screams incessantly about Indian burial grounds and something cold and wicked this way coming.

For a moment you might believe they're all killing time; Cusack especially seems adrift, in it for the paycheck in early scenes that suggest he has little to do and nowhere to go in the savaging thunderstorm. But it turns out they're supposed to be cardboard cutouts, stand-ins for something else -- for what exactly, I wouldn't say, because that blows the gimmick Cooney and Mangold have in store, but their intentions become clear toward the film's end. Theirs isn't a horror movie (it just looks like one), but a clever appraisal of our relationship to films and what we expect from them: visceral thrills, in this case, that add up to a much larger pleasure. The studio is leading its audience down the wrong path; Identity has no intention of scaring, but of amusing, confusing and critiquing our belief in dopey genre films and the people who live and die in them.

The twist is suggested at the film's beginning, as a psychiatrist (Alfred Molina) listens to his interview with a convicted killer (Pruitt Taylor Vince) 24 hours away from execution; new evidence has arisen to warrant a midnight hearing, of which we see bits and pieces during the motel massacre. At first it all seems so much nonsense, a distraction. What is the point? But keep in mind that Identity was written by a man who wrote and directed two movies about a dead serial killer who returns as a homicidal snowman. Identity is an outright blast, so fun it's -- pardon -- scary. How can you not adore a movie in which Rebecca De Mornay is cast as a petulant movie star no one really remembers? "Didn't you used to be that actress?" asks grimy motel manager Larry (John Hawkes); soon enough she winds up nothing more than a head in the spin cycle. Oh, the humor.