(CNN) The dominant themes of Mel Gibson's filmmaking career have been extreme violence, history and religion. Small wonder that the actor would find a project that combines them all to begin his comeback climb with the fact-based war drama "Hacksaw Ridge," ending a decade-long directing hiatus.

A stirring, astonishing tale of bravery billed without qualification as "a true story," the movie is painfully earnest -- indeed, almost old-fashioned, other than its graphic rendering of what World War II looked like up close and personal, specifically during the battle to capture Okinawa in 1945.

What's lacking, in keeping with the bludgeoning approach Gibson brought to "The Passion of the Christ," is any of the nuance that has become a staple of modern war movies. That includes, in perhaps "Hacksaw's" closest recent cousin, Clint Eastwood's tandem of "Flags of Our Fathers" and "Letters From Iwo Jima."

Instead, Gibson (working from a script credited to Robert Schenkkan and Andrew Knight) dutifully chronicles the story of Desmond Doss -- the first conscientious objector to receive the Medal of Honor -- in three distinct chapters: his Blue Ridge Mountains upbringing by a religious mother (Rachel Griffiths) and abusive father (Hugo Weaving), a veteran of World War I, and courtship of future wife Teresa (Dorothy Schutte); basic training, as the military tries to drum him out of the service for his beliefs; and the war, a melee of ravaged limbs and spurting wounds.

Despite being a Seventh Day Adventist, Desmond (Andrew Garfield) enlists in the army, determined to help the cause without violating his principles by saving lives as a medic. It falls to a tough sergeant (Vince Vaughn) and by-the-book captain (Sam Worthington) to try forcing him to quit, in part by turning his rifle battalion against him.

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