The Boys in Company C (1978)

This war drama (which prefigures the later "Full Metal Jacket") follows the lives of five young Marine inductees from their training in boot camp in 1967 through a tour in Vietnam in 1968 that quickly devolves into a hellish nightmare. Disheartened by futile combat, appalled by the corruption of their South Vietnamese ally, and constantly endangered by the incompetence of their own company commander, the young men find a possible way out of the war. They are told that if they can defeat a rival soccer team, they can spend the rest of their tour playing exhibition games behind the lines. But as they might have predicted, nothing in Vietnam is as simple as it seems.