All games need conflict. Most of the time the player's objective is blocked by several thousand faceless, nameless mooks throwing themselves in the path of danger with all the fervor of a headless chicken. But behind those mooks lies the antagonist, the figure that has been working against the hero all along. The best rivalry showdowns are between two solitary figures, foils of one another. These are the kinds of rivalries the player waits the entire game (or series) to settle once and for all. Here are some of the best one-on-one showdowns in gaming history.

7. Solid Snake vs. Liquid Snake in Metal Gear Solid

Cut from the same cloth—or rather, grown from the same Petri dish—Solid and Liquid are both clones of the same super-soldier. Liquid Snake was created from all the best aspects of the cold-war hero Big Boss, while Solid Snake was made from the inferior genes of the same man. However, because the American government couldn't justify keeping a soldier with such a sinister British accent on staff, Solid Snake became the series' hero, and the perfect-on-paper Liquid was kept from his birthright. Believing himself to be the genetically weak twin, Liquid's inferiority complex drives him to do what any of us would, take over a secret Alaskan military base and hijack a doomsday device.

Snake (the solid one) must wind his way through Liquid's facility, defeat an animal-themed squad of super soldiers and disarm Metal Gear, a nuclear-powered robot T-Rex (did I mention this was a Japanese game?). But before Snake can hang up his skin-tight rubber jumpsuit and call it a night, the two rivals settle their dispute the way they both knew they inevitably had to: a man-to-man fist-fight on the head of a metallic dinosaur's corpse. Never change, Japan.