Darkest of Days for the Microsoft Xbox 360 is a first-person shooter where players travel through time to iconic battles from history. The game's genre blends sci-fi elements with historical warfare as the protagonist, Alexander Morris, is recruited by a mysterious organization to preserve the timeline. Players engage in combat across different eras, from the Civil War to World War II, using period-appropriate weapons alongside futuristic firearms. With a mission to save key individuals from death, the player must navigate both the chaos of warfare and the responsibilities of a temporal guardian.