4. Call of Duty: Black Ops 2
Call of Duty: Black Ops 2 is the sequel to Treyarch's first Black Ops game. It's set in its own universe and not in whatever fiction Infinity Ward cooked up in the Modern Warfare trilogy.
Black Ops 2 is the first game in the Call of Duty franchise to feature a completely futuristic setting, with weapons and technology that remain theoretical at this point in time. Also diverging from the previous Call of Duty games is the addition of a branching storyline and a narrative that takes into account the decisions you make throughout the game.
More than just a numbered sequel or a rehash of the Call of Duty franchise, Black Ops 2 presents itself as an evolution of the series—not unlike how Battlefield 3 is to Battlefield 2.