“As long as you can still grab a breath, you fight,” Hugh Glass (Leonardo DiCaprio) tells his ailing son Hawk (Forrest Goodluck) in the opening moments of The Revenant, the latest from Birdman director Alejandro González Iñárritu. These are words Hugh himself will soon live by, and an apt message for anyone struggling through a hardship.

Such words also describe the troubled production of the film: It was shot in chronological order over a span of nine months in (mostly) Northern Canada, using only natural light, meaning they could shoot for only small portions of each day. DiCaprio got the flu multiple times, and some crewmembers quit due to the harsh conditions — one even called it “a living hell.” The budget soared to $135 million and the frigid weather was a constant headache — a makeup bag even froze to the floor.

None of this, of course, should matter to us in the end, because the movie is either good or it isn’t. While the acting and cinematography are tremendous, watching The Revenant is an altogether unpleasant experience. When it’s over, you’ll feel dirty, like you need a shower. There’s not one scene, moment, or even a glimpse of anything like happiness. The entire picture is a glum exercise in survival that only gets worse, never better.

Based on a true story, DiCaprio plays Hugh, a fur trapper on a hunting expedition that’s under constant threat of attack from the natives and French hunters. It’s the 1820s in a lawless land, and fur pelts are the common currency; the more you bring home to sell, the better. Pelts are also easily, are often, stolen. While separated from his group, Hugh is mauled by a grizzly bear in one of the most frightening, brutal and horrifying scenes I’ve viewed onscreen; three weeks of rehearsal and a computer-generated bear made this a haunting, unforgettable sequence.

Hugh is cared for by his fellow hunters, but slowing them down. Believing Hugh’s death is near, the captain (Domhnall Gleeson) asks two men – Chip (Will Poulter) and Fitzgerald (an excellent Tom Hardy) – to stay behind with the teenage Hawk and Hugh to make sure the man gets a proper burial. Fearing attack, Fitzgerald panics, kills Hawk and buries Hugh alive before leaving to catch up with the other men. What proceeds is nearly two hours of Hugh struggling to find those who wronged him and enact his revenge, all while terribly injured and battling the elements.

Smaller moments, such as Hugh trying to drink water only to have it come out through the gash the bear left in his neck, may be more notable, but consider DiCaprio’s performance as a whole: He goes about an hour with no dialog at all, relying on his bearded, marred face and heavy breathing to relay all that Hugh is thinking and feeling. His character also endures freezing rapids, starvation, frigid temperatures, constant danger and falling off a cliff. Most of the time, all we hear is groaning and struggling, and in a way that says it all. Iñárritu and Mark L. Smith’s screenplay (based in part on the novel by Michael Punke) doesn’t need to give him more dialog, because his motivations are obvious: Survive and avenge.

One reason Hugh’s desperation feels so palpably real is two-time Oscar-winning cinematographer Emmanuel Lubezki (Gravity), who creates a bold and daring visual experience. His camera moves swiftly and fluidly among the men and the landscape, with frequent closeups of characters showing the anguish felt by all due to the elements. Note the low angle shots that look up to faces, often with trees high above their heads, and shots of mountains and other natural elements, all of which suggest how insignificant humans are to their larger surroundings. They may be fighting one another, but the common enemy of nature is their biggest foe of all.

At 156 minutes, The Revenant is an endurance test to sit through. Hugh’s arduous trek takes him from one near-escape to the next, and after a while the awfulness of his situation becomes overwhelming. This is an audacious, brave movie, an original tale told with real guts and conviction, but it’s not enjoyable to watch. And yet, there’s so much to admire about it, you cannot deny its substance and all that it does well. You may not like The Revenant, but you will respect it.