Brain-bending sci-fi loses its snap when treated like homework, but you won't really understand Looper unless you prepare by watching a few episodes of Moonlighting. These will reacquaint you with the languid glances, open-mouthed smirks and corona of intense self-satisfaction that glowed from the young Bruce Willis. And they will prime you to better appreciate the lead Looper performance of Joseph Gordon-Levitt, who delivers a precise, slyly parodic mimicry of Willis circa 1987. The ubiquitous trailers have revealed that Gordon-Levitt plays the same character as Willis, and that he's been given a makeup job to recall a skinnier baby Bruce, but the previews barely scrape the forgery of mannerisms. Die hard and leave a reanimated corpse—maybe that's the lesson. 

Gordon-Levitt has been a regularly mesmeric actor for the last decade (though he's probably best known as a sidekick in Christopher Nolan movies, which waste him), so it's peculiar that his breakthrough comes through impersonating an icon. But that paradox fits the aims of director Rian Johnson, who used Gordon-Levitt as a teenage Sam Spade in Brick, and with Looper throws 100 years of film noir into a blender. The picture is set in the future—2040, with a brief discursion to 2070—but it is breathlessly in love with movies past. Early buzz is praising the originality, but Johnson has in fact succeeded at repurposing familiar elements in unusually satisfying ways. At various junctures, Looper reminded me vividly of the following antecedents: Point Blank, Donnie Darko, Once Upon a Time in the West, Blade Runner, Chinatown, D.O.A., The Omen, Witness and the anime Akira. It's like a Girl Talk record if Greg Gillis sampled classic jazz riffs. Forget neo-noir: This is retro-neo-futurist noir. 

One of these mash-ups demands further review: How is it possible that Gordon-Levitt and Willis meet in a roadside diner, clutching sawed-off hand cannons called "blunderbusses," as two incarnations of the same hired gun, an amoral hard case named Joe? But not too much review. Old Joe tells Joe not to think about the matter too hard, or they'll be there all day making diagrams out of the drinking straws. Anyway, voice-over gives sufficient explanation: "Time travel hasn't been invented yet, but 30 years from now it will have been." So it's a one-way trip, made only by the doomed souls wished into a cornfield by the mob that hires Joe to blow them away. That hit list is supposed to include Joe himself—or Old Joe, technically. But getting to that appointment involves a narrative shell game so jaw-dropping that it makes the closed loop feel open to any possibility. The movie just about fulfills that promise. Its second half, undermining Willis' heroic image nearly as completely as Moonrise Kingdom did, shifts focus from time travel to telekinesis, then actively questions whether it's possible for a person to make an original decision.

Is it possible for a movie? "This job doesn't tend to attract the most forward-thinking people," Joe muses. Looper thinks backward. It is that rare science fiction movie as interested in style as plot, making it keenly aware of how bound we are to whatever came before us. In an era when computer graphics lend themselves to empty triumphalism, dystopia may be the only trustworthy action-movie genre left. It knows how the past frustratingly repeats itself. Playing a mob boss, Jeff Daniels (wearing a thicket of neck beard and pilfering his scenes) rails against kids without the imagination to try anything new, enslaved to vintage. But in resurrecting sights and faces we never thought we'd see afresh, Looper knows what movie lovers always feel: The past is never dead. It's not even past. And it's got a gun. 

Critic's Grade: A

SEE IT: Looper is rated R. It opens Friday at Lloyd Center, Cedar Hills, Clackamas, Eastport, Mill Plain, Cornelius, Oak Grove, Bridgeport, City Center, Division, Evergreen Parkway, Hilltop, Movies On TV, Sherwood, Tigard, Sandy.