Mel Gibson is such a polarizing figure that it’s easy to forget or underestimate his considerable filmmaking talents.

As great of a movie star as Gibson was in his heyday, there’s a reason he won his Oscars for directing and producing “Braveheart”: The man has a gift for epic, visceral storytelling.

“Hacksaw Ridge,” Gibson’s first directorial effort since “Apocalypto” in 2006, provides an ideal vessel for these particular skills.

It is a gargantuan production about Desmond Doss (Andrew Garfield), a real-life conscientous objector who nonetheless enlisted in World War II and, while refusing to touch a gun, saved countless lives under perilous conditions as a medic during the Battle of Okinawa in 1945.

The battle occupies the third act of the picture and in it Gibson captures the unrelenting brutality of combat in Japan with a steadfast devotion to every last bit of blood and guts. He’s done this before as a filmmaker, in “Braveheart,” “Apocalypto” and, notably, “The Passion of the Christ,” but familiarity with the filmmaker in this mode hardly lessens the sensory impact of every sudden explosion, piercing bullet or burst of shrapnel.

Battle scenes without context, however expertly rendered, simply can’t register as anything more than spectacle. The Okinawa scenes here penetrate as they do because Gibson has found an original WWII story to tell, one rife with heroism that is both genuine and unexpected, which climaxes as Doss scrambles to rescue his comrades amid the carnage.

Besides graphic violence, Gibson’s movies (other than “The Man Without a Face,” of course) are unified by their overt religiosity. His approach in that area here borders on heavy-handedness, particularly in the cornball depiction of Doss’ rural Virginia hometown.

But this picture earns the angle: Doss not only preaches a deep and abiding belief in the Bible; he actually practices its teachings.