Pulsing with gung-ho machismo, the Desert Storm war drama Jarhead is like having one of those manly energy drinks injected right into your veins. There is a conscience to be found beneath the bravado, but it is the grunting that wins out. In the movie, the American soldiers get juiced up by watching various war flicks, especially Apocalypse Now, and Jarhead should have no trouble serving just such a purpose in conflicts to come. With mesmerizing moments of visual poetry from director Sam Mendes (American Beauty) and a revealing, vein-popping lead turn by Jake Gyllenhaal.