War movies do not naturally lend themselves to sequels. Many of the genre's greatest films center on a specific battle, mission, or real-life event, which means the story has usually reached its natural conclusion by the time the credits roll. This is particularly true of World War II movies, where trying to manufacture another chapter can easily undermine what made the original work. There are exceptions, however. Some war movie sequels have found a convincing reason to return by sending familiar characters on another mission or approaching the same conflict from an entirely different perspective. Others abandon historical realism almost...