BioShock Infinite

BioShock Infinite swapped Rapture's ocean depths for Columbia's sky-high theocracy, and the result is one of the most intellectually ambitious shooters ever made. The relationship between Booker and Elizabeth drives the narrative, and Elizabeth's AI companion behavior — tossing you ammo, reacting to the world, opening tears in reality — set a new standard for NPC partners. The ending ties itself into knots of multiverse theory that players are still debating a decade later. Ken Levine reached for something almost impossibly ambitious, and largely delivered.