How many thousands of pounds has Christian Bale lost and gained and lost again from The Machinist to Batman Begins to Werner Herzog’s latest movie? Director and star could practically write a diet book—were it not for the requirement of being shot down in a plane, starved in a Laotian prison, plucking off leeches, running through the jungle, and eating raw snakes. Which is actually what happened to U.S. naval aviator Dieter Dengler in the early days of the Vietnam War. Herzog previously told the story in his 1997 doc, Little Dieter Needs to Fly; this is his somewhat embellished version of the true-life survival tale. It’s a Rambo movie without Rambo: German-born Dengler is a patriotic aviator who thinks the nascent Vietnam war will be over in a few weeks. (Sound familiar?) Yet throughout his ordeal, with Steve Zahn and a gaunt Jeremy Davies tagging along, his innocence remains essentially intact, his optimistic character unchanged. He basically gets Gitmo-ed and ends up smiling. True to Dengler, perhaps, but the movie never achieves the madman-in-nature intensity of Herzog’s Kinski period. One senses Herzog is more fascinated with the opening archival footage of slo-mo orange napalm blossoms in the endless green jungle: The bombs have a fiery life to them, while the bomber remains a drone.