“It’s okay, son. I know you want this to be over.” This is a brave voiceover with which to open a movie that consists of two-and-a-half hours of almost nonstop violence, injury, and privation. In context, it serves as a father’s comforting words to his son. But it could as easily represent a filmmaker’s warning to his audience.

Fortunately, while Alejandro G. Iñárritu’s The Revenant is frequently a grueling experience, it is also a profoundly rewarding one, a film that balances beauty and brutality in extraordinary equipoise.

Based on the 2002 novel by Michael Punke (itself based on the experiences of the real-life fur trapper Hugh Glass), the movie tells a primal story of survival and vengeance. In 1823, a large hunting party is on the verge of completing its six-month mission in the wintry wildernesses of Montana and South Dakota when it’s set upon by a band of warriors from the Ree tribe. After most of the men are killed in the encounter, those remaining ask their experienced tracker, Glass (Leonardo DiCaprio), to guide them safely back to their barracks outpost.

Glass, however, is soon mauled by a bear, and though he manages to kill the animal, he’s direly wounded—his throat slashed open and his back torn to ribbons. Presuming his imminent death, the leader of the expedition, Captain Henry (Domhnall Gleeson), leaves him behind with three men to bury him when the time comes: Glass’s half-Pawnee son, Hawk (Forrest Goodluck); another young hunter, Jim Bridger (Will Poulter); and an older man, John Fitzgerald (Tom Hardy), with mercenary motives and no love for Glass. In short order, Fitzgerald kills Hawk and tricks Bridger into leaving Glass for dead.

But Glass does not die. He rises from his shallow grave and, like Hercules with the Nemean lion, wraps himself in the pelt of his bear. He then crawls, floats, and hobbles across hundreds of frozen, desolate miles in a quest to find Fitzgerald and avenge his son. Along the way, he’s hounded by hostile natives (more than once), tumbles down cliffs (more than once), and faces death by starvation and exposure (more or less continuously).

From this simple tale, Iñárritu has constructed an epic fable of uncommon grace and resonance, a film that, like its hero, achieves a kind of transcendence. The director is immeasurably aided in this achievement by his cinematographer, Emmanuel Lubezki. Shooting exclusively with natural light, Iñárritu and Lubezki craft a winter landscape at once pitiless and ravishing, a universe of muted grays: gray skies, gray snow, gray rock. (If these vistas recall Terrence Malick, it’s no coincidence: Lubezki shot the director’s last four films.)

As with Lubezki’s last two major projects, Gravity and Birdman, this isn’t merely an aesthetic achievement but a technical one as well. The attack that opens the film is a tour de force of action choreography, with tracking shots reminiscent of Lubezki’s work on Children of Men. And the bear attack is a complete stunner, without any true parallel that I can name. Moreover, the demands of weather and natural light forced principal photography to take place in a dozen locations in Canada, Argentina, and the United States, and a number of crew members quit or were fired over the course of the grueling shoot. The resulting film, however, has made Lubezki the odds-on favorite to win an unprecedented third consecutive Oscar for cinematography.

Hardy is marvelous as Fitzgerald, a self-justifying brute of a man with twitchy eyes and deep scars (some of them literal: He’s the survivor of an incomplete scalping). As he’s done in the past, Hardy vanishes utterly into the role; those unaware of his participation in the film might struggle even to recognize him.

And Leo? He is a more complicated case. He’s surely worthy of the many accolades that are being thrown his way. But I’m not certain how much of his work onscreen—and he is present in nearly every scene—is properly categorized as “acting.” DiCaprio’s commitment to the role is beyond dispute. The actor spent nine months in remote locales, in the snow and in icy water, frequently on the verge of hypothermia. He is completely persuasive in the role, but perhaps this is in part because onscreen he is enduring—obviously in lesser ways—the travails endured by Glass. Factor in that his character is largely mute throughout the film and that the emotions he conveys are inevitably both large in scale and limited in variety, and I am, again, unsure of how exactly to categorize the performance. It is, however, unquestionably a powerful one.

The Revenant is not without its flaws. Though there are intimations of moral complexity and ambiguity early on, they are abandoned in favor of disappointing dichotomies: Characters are gradually sorted into the uniformly kind, tolerant, and trustworthy on one side; and the lying, venal, and bigoted on the other.

And then there is its length. As stunning and immersive as The Revenant may be, 156 minutes is a long time for viewers to endure a portrait of endurance. (After all that has come before it, the movie’s final, bloody confrontation veers dangerously close to comedy.) Iñárritu’s film is one very much worth seeing, but be forewarned: You—like DiCaprio, and like the real Glass before him—will be out in the cold for a long time.