The hero of Waterworld, the futuristic glub-glub spectacular, is a sci-fi seaman known as the Mariner (Kevin Costner), who has webbed toes, gills behind his ears, and long hair pinned back into a stringy, aquatic ponytail. Over the course of the movie, he drinks his own (recycled) urine, gets dunked in mustardy ooze, and spends so much time leaping in and out of the grunge-green ocean deep that, at various points, I felt like toweling him off and buying him a blow dryer. In Waterworld, which is set in a distant postapocalyptic future, the polar ice caps have melted, covering the earth in an ocean of seemingly unbroken vastness. The Mariner cruises through this wet wasteland in a trimaran the size of a small city block. When he outraces a bunch of punks on Jet Skis, what's thrilling about the sequence a kind of regatta from hell is seeing one person leap around to work that gigantic triple-pontooned boat. The Mariner doesn't just operate on water; he lives it, breathes it, owns it.
Waterworld is nothing if not a triumph of large-scale action-adventure logistics. Directed by Kevin Reynolds, who collaborated with Costner on several earlier projects (notably Robin Hood: Prince of Thieves), the film may have taken 166 days to shoot and come in at a preposterous cost of nearly $200 million, but it's no Heaven's Gate. The very thing that made it such a high-profile production nightmare the challenge of staging an entire movie on the ocean surface pays off in the film's visually enveloping, woozily off-kilter atmosphere, which effectively creates the sensation that water is the closest thing there is to solid ground. What Waterworld isn't, by any stretch, is a triumph of originality. In its story and characters, its ''visionary'' junk-collage aesthetic, this lavishly detailed, rather ponderous popcorn movie is such a brazen knockoff of 1981's The Road Warrior that it's as if George Miller's future-shock demolition classic had been remade inside the world's biggest bathtub.
Costner's Mariner is, of course, a gloss on Mel Gibson's Max, the hard-shelled nihilist loner whose empathy has been burnt away by the day-to-day hell of survival. Looking for a place to barter the soil he gathers from the ocean floor, he stops at a giant floating ''atoll,'' whose bedraggled residents have built a scrap-heap city from the detritus of civilization. Where The Road Warrior featured a roving band of punk-pirate motorbikers led by a facially mangled psycho known as the Humungus, Waterworld features a roving band of punk-pirate water bikers led by a facially mangled psycho known as the Deacon (played by Dennis Hopper). Where The Road Warrior had Max rediscover his humanity by bonding with the Feral Kid, Waterworld has the Mariner rediscover his humanity by forming a fractious ''family'' with a wild child named Enola (Tina Majorino), who has a map leading to dry land tattooed on her back, and the kid's beautiful guardian (Jeanne Tripplehorn). Finally, where The Road Warrior had those brilliant, two-lane-blacktop homicide derbies, the most spectacular car chases ever filmed, Waterworld has...some reasonably okay action scenes. For all its epic scope, the new film moves to a waterlogged rhythm that doesn't really mesh with the exhilaration of pure kinesis. It's The Road Warrior without speed.
The difference in the tempo is reflected in the temperament of the star. Kevin Costner has been growing more and more recessive as an actor; by now, there doesn't seem to be much to him aside from his dour attitude and sexy laconic stare. But his downbeat surfer-bum affectlessness works for Waterworld. In a universe built on pitching waves, a hero can't afford to waste energy imposing himself. He has to go with the flow, and Costner, staring out at the horizon with leathery inscrutability, does a convincing job of playing the Mariner as the world's most jaded lifeguard. (He's at his best using himself for shark bait.)
As the Deacon, Dennis Hopper gets to parade around brandishing a shaved head and blown-out eyeball, but there isn't much personality to this despot, and even less to his hooligan band. Unlike The Road Warrior, whose villains were truly shocking they had an outsize Aussie kinkiness Waterworld lacks a pungent sense of evil. And when the film unveils its most sensational set, the rusted-out carcass of the Exxon Valdez, the retro-future spectacle would be kickier if Costner and Reynolds didn't seem to think they were making an environmental statement. Waterworld lives up to its title for two hours, you forget that dry land exists but anyone who spends this much money making a movie this impersonal should think twice before preaching to an audience about squandered resources. B