A full decade has passed since Mel Gibson’s last film, “Apocalypto,” but “Hacksaw Ridge” proves that he has lost none of the directorial savvy he demonstrated in it, or in “Braveheart” and “The Passion of the Christ.” Based on a true World War II story—about Desmond Doss, a conscientious objector who refused to carry a gun but saved more than fifty of his fellow soldiers during the bloody battle of Okinawa (and received the Medal of Honor for his heroism)—it’s distinctly old-fashioned as drama. But in the first half of the picture Gibson uses tried-and-true tropes so effectively that you don’t mind how hokey they actually are, and he stages the battle sequences that fill the second half with such assurance that those craving violent action will be sated.

The obvious point of comparison is to another fact-based war film, Howard Hawks’ 1941 “Sergeant York,” in which Gary Cooper played the World War I sharp-shooting soldier whose faith kept him from using a gun in combat until he took one up to save his men. Doss, however, never succumbed to that impulse; as a medic he lugged wounded Americans back to the cliff they had climbed to attack the Japanese defenders, and lowered them down to waiting comrades with a jerry-built rope harness. That he managed to do so while in direct danger himself seems miraculous—and Gibson, of course, is not one to downplay that. His directorial strengths have never veered toward subtlety.

That fact is quite evident in the first half of the film, which depicts Doss’s troubled home life, his unlikely romance, his enlistment, and his boot camp training. This part of the picture actually seems to have come out of the 1940s, employing the sorts of melodramatic clichés that Hawks or John Ford would not have blushed at. We first meet Doss as a young boy (Darcy Bryce) roughhousing in the Blue Ridge Mountains of Virginia with his brother Hal (Roman Guerriero). His loving mother Bertha (Rachel Griffiths) dotes on the boys, but their abusive father Tom (Hugo Weaving) drinks to forget the deaths of his home-town comrades in World War I and goes into violent rages against his sons and his wife. Desmond’s turn to pacifism comes when he seriously injures his brother during a scuffle, and his refusal even to touch a gun again comes when, now grown and played by Andrew Garfield, he intervenes when Tom threatens Bertha with one and he takes it away from him.

But not all is unhappy for Desmond, whom Garfield instills with an aw-shucks demeanor that would have made Cooper proud, though because of the resemblance he might also remind you of Anthony Perkins doing the shtick. He romances pretty nurse Dorothy Schutte (Teresa Palmer), with whom he of course falls in love at first sight, and the two plan to marry.

But Pearl Harbor intervenes, and Desmond and Hal (Nathaniel Buzolic) enlist, much to the disgust of Tom. That introduces a boot camp sequence that includes tough drill sergeant Howell (Vince Vaughn, in one of his better recent turns) and a stable of stereotypical comrades that might have come out of a studio war picture of the time, with nicknames like “Hollywood” and “Ghoul.” His refusal to accept a rifle, citing his beliefs as a Seventh-Day Adventist, earns him treatment from Howell and officers like Captain Glover (Sam Worthington) that is aimed at compelling him to quit, and disdain from his fellow trainees, most notably the supremely macho Smitty (Luke Bracey). Doss is eventually threatened with a court martial, and only an unexpected intervention—unexpected, at least, if you are unacquainted with the twists of forties melodrama—intervenes to save him.

Cut to 1945 Okinawa, and one enters a very different cinematic world, one that recalls the brutal battle sequences of contemporary war films, though even here cinematographer Simon Duggan works with a lush palette. Doss, now a proper medic, watches in horror as his comrades are cut down by withering enemy fire. He helps as many as he can—Smitty and Howell are among those who are wounded and come under his care—and remains behind after most of the surviving American forces have clambered back down the cliff they had earlier ascended to confront the entrenched Japanese. Over the course of the night he roams around the battlefield, carrying those he finds still alive and lowering them down the cliff to be carted off to the increasingly crowded MASH facility, much to the amazement of those below.

Gibson stages these sequences with considerable punch and John Gilbert edits them skillfully: viewers who experience difficulty seeing severed limbs and gruesome deaths, courtesy of the fine effects team, should be forewarned. But while giving no quarter in the scenes of actual combat, the ultimate emphasis is on Doss’s heroism in putting himself in continued danger to save the wounded. It would be unjust to say that Garfield comes into his own here, because his performance has from the beginning been superior. The intensity he brings to these later scenes, however, is worthy of special mention—and makes the character worthy of the reverence with which he’s now treated by the rest of the men, so much so that the swelling score by Rupert Gregson-Williams actually comes across as counterproductive.

Among the supporting players, Vince uses his verbal dexterity to make Howell’s insulting excoriations of his platoon sure winners, and Weaving cuts a powerful portrait of a man tormented by his own wartime experience. Palmer makes the supportive Dorothy a stronger presence than one might have expected, and Bracey provides stalwart support, especially in the scenes when Smitty converses with Doss amidst the carnage on Okinawa. The rest of the cast acquit themselves well, though except for a few stray moments few stand out.

It might seem curious to call a war film an old-fashioned crowd-pleaser—unless it’s a comedy, of course—but Gibson’s is. And the real-life footage of a crusty old Doss at the end (accompanied by testimony from others who knew him) caps it off perfectly.