"Jarhead" is a war movie about a generation of soldiers who grew up watching war movies — which only reminds us how superior those first films were.

"Apocalypse Now," "The Deer Hunter," "Platoon," "Full Metal Jacket" — the Marines of "Jarhead," based on the best seller by Gulf War veteran Anthony Swofford, know them all by heart. They are the military equivalent of "The Rocky Horror Picture Show." They serve as training film, documentary, comic relief and porn, all at the same time.

Director Sam Mendes and screenwriter William Broyles Jr. — himself a Vietnam vet — know that you've seen them all, too, and make no attempt to distance themselves from their predecessors. They've borrowed, copied and sometimes even inserted entire scenes as freely as Sean Combs samples '70s and '80s hooks for his rap songs.

On the one hand, this was a smart tactic — it's what actually happened, at least according to Swofford, so they're being true to reality. But Mendes and Broyles also know that they're visiting familiar territory, so they strike a pre-emptive blow at those who will naturally find similarities.

On the other hand, the very presence of these earlier films in any form — a clip of the iconic helicopter scene from "Apocalypse Now," for example, with Wagner's "Ride of the Valkyries" blaring across the beach in all its thunderous glory — shows how little new insight "Jarhead" has to offer.

The entire opening sequence is practically a shot-for-shot remake of the top of "Full Metal Jacket," and it comes at you just as hard and fast.

Jake Gyllenhaal's Swofford — or "Swoff," as he's known — stands at attention in the barracks alongside his fellow jarheads (named for the style of their buzz cuts) and endures a litany of increasingly profane, darkly hilarious abuse from his drill sergeant. ("Are you in love with me, Swofford?" "Sir! No, Sir!" That's about all we can repeat here.)

Serving as narrator, Swoff comments sardonically on the routine chaos of daily life in the Marine Corps. He is to Operation Desert Storm what Yossarian was to World War II in "Catch-22," and in Gyllenhaal's increasingly versatile hands (and surprisingly buff body), the character visibly, believably hardens before eventually crumbling.

The absurdity of the training ritual — and of going off to a war in Saudi Arabia that will end almost quickly as it began — provides a powerful source of satire, especially through the eyes of its British director. Mendes again uses his outsider status to cast a harsh eye on the some of the more ridiculous elements of American society, as he did with his Oscar-winning "American Beauty."But "Jarhead" too often feels repetitively episodic: one training session after another, one hideous cruelty after another, one day without action after another, sapping the film of narrative momentum. Yes, the tedium is inevitable. This is what happened to them: seemingly endless uselessness, until one day ... nothing."We throw hand grenades into nowhere," says Swofford in a voiceover. "We fire at nothing. And we hydrate."The film itself shouldn't feel tedious, though. You may find yourself repeatedly checking your watch during the second hour, despite typically textured performances from Jamie Foxx as Swofford's staff sergeant and Peter Sarsgaard as his sniper partner, and despite the gorgeous cinematography from Roger Deakins, the frequent Coen brothers collaborator and five-time Oscar nominee.As the film descends into its darkest period, Deakins' depiction of a burning oil field is stunning — a surreal swirl of orange and black, like some beautiful version of hell. And his shots of the desert, usually through an eye-level, hand-held camera, make the dry vastness and shimmering sun feel palpable.Then again, the film's frequently bleached-out look calls to mind yet another war movie: David O. Russell's "Three Kings," which was refreshing in its rendering of the futility of Desert Storm — when it came out six years ago. Now there's a movie that had something to say.