Each game involves protagonist Solid Snake (or someone else codenamed Snake) sneaking around maps and avoiding enemy soldiers. Snake is armed with various weapons, most of which exist in the real world. At certain points in the game, Snake has to fight various bosses who usually possess different superhuman or supernatural abilities. In most games, the penultimate boss is the latest incarnation of the weapon Metal Gear, with following bosses being one-on-one confrontations with that game's main antagonist.