On August 7, 1974, French street performer Philippe Petit captured the world's attention by attempting—and pulling off—the impossible: a wire-walking performance between the roofs of the World Trade Center's North and South Towers, 1,350 feet in the air. This part-mad, part-amazing feat was written about in Petit's 2002 memoir "To Reach the Clouds," later covered in James Marsh's 2008 documentary "Man on Wire," and now portrayed in a $35-million feature film from writer-director Robert Zemeckis (2012's "Flight") and co-scribe Christopher Browne. When "The Walk" takes literally to the sky in the film's second half, it is everything one could want it to be: engaging, stressful, terrifying, majestic, and oddly inspiring. To get there, however, the script must tread a lot of sketchily developed biographical filler, set predominately in the year leading up to his monumental stunt. It is arguable if Petit's life beyond his one major claim to fame warrants a two-hour picture—at least insomuch as it is captured here—but the long setup is worth wading through to get to the awesome payoff.

24-year-old Philippe Petit (Joseph Gordon-Levitt) is working the streets of Paris, performing magic, juggling and balancing acts for small receptive crowds, when a fateful trip to the dentist leads him to a magazine in the waiting room about the construction of New York City's World Trade Center. The identically sized towers are supposed to be the tallest buildings in the world, and Petit fast becomes enamored with the thought of traversing them, free of a safety line. Following training with aging wire-walking extraordinaire Uncle Rudy (Ben Kingsley), Petit and his new girlfriend, street musician Annie Allix (Charlotte Le Bon), head to Manhattan to fulfill his mission. With the buildings nearing completion, he and his appointed crew—including photographer Jean-Louis (Clement Sibony) and mathematician-with-a-fear-of-heights Jeff (César Domboy)—have but a limited window to go undetected as they perfect their wild plan and foolproof every last detail of their operation.

"The Walk" tells of a true-life endeavor beyond the realm of comprehension, an act so unthinkable any rational person should get dizzy just thinking about it. Dramatizing it onscreen is another story altogether. As Dariusz Wolski's (2013's "The Counselor") camera steps foot onto a slim cable wire suspended 110 stories above ground—or at least appears to, courtesy of the film's stupendous visual effects artistry—the viewer is led to readily believe Joseph Gordon-Levitt (2013's "Don Jon") really is balancing on a thread between life and death, transcendence and insanity. The climactic 45-minute segment where Petit takes to the clear blue as onlookers stand, mouths agape, on the streets below, is pure cinema. Exasperatingly thrilling, even vertigo-inducing, this extended set-piece grabs its audience while daring them to look away, knowing full well they won't be able to do so. Reaching this part of the story, however, takes a certain amount of patience. The opening act set in Paris goes on too long, revealing a coil-thin narrative that seems to be biding its time leading up to the main attraction of the title. At least the picture is gorgeous while stretching out the running time; Wolski's images appear to have been dipped, one at a time, in the golden hues of summer sunlight and twilight hour.

Joseph Gordon-Levitt would probably not be most people's go-to casting choice to play the thickly accented French wire-walker Philippe Petit, and yet he instantly sells the illusion the second he speaks. This is a delicious performance of impressive physical dexterity. Gordon-Levitt perfectly captures the wonder and drive of Petit's arguably lunatic ambition, even if he isn't given the chance to dig much deeper; a brief scene where his father kicks him out of the house over his choice in profession is over and done with in moments, left markedly underexplored. As Annie, Charlotte Le Bon (2014's "The Hundred-Foot Journey") has a way about her, an eye-catching soulfulness that suggests there is far more going on behind her eyes than what the script demands. Le Bon's character is treated almost as an afterthought as the movie takes the time to establish her relationship with Philippe and then does strikingly little with her. At every turn, Annie is all for her boyfriend's WTC stunt, and doesn't once so much as voice a concern about his safety. Depending on one's view, this could come off as supportive or the actions of someone who isn't quite emotionally invested—and it may be the latter, based on how this romance ultimately works itself out.

"The Walk" provides a trial-by-fire catharsis to acrophobics everywhere, but it certainly won't rid them of their fears. As biopic, the film is slight. As a heist caper, it is more successful, building deliberately to a showstopping finale. Philippe Petit did not solve world hunger or cure a debilitating disease. He was a skilled tightrope performer, possibly a little crazy, who, as the picture touts, "showed the world anything is possible." In a post-9/11 existence where the very towers Petit walked across are no more, there is a poignant, wisely unspoken undercurrent that the story would likely be lacking were those same buildings still standing. "The Walk" isn't terribly deep, but all the drama it needs is left right up there on that cable, a quarter-mile from terra firma and one step away from life itself.