Naughty Dog has developed an AI system called 'Balance of Power'. A new gameplay mechanic is a feature the developers call 'dynamic stealth', meaning that there are many different types of strategies and techniques that the player can use at any given time as they approach a new situation, to which enemies will react differently. The player fights off the Infected-former humans infected by a mutated strain of the cordyceps fungi-and the Survivors-humans that are not infected, but are hostile towards Joel and Ellie. The game involves gun fighting, melee combat, and a cover system with no preset cover locations, only crouching near objects and navigating normally. The Last of Us uses a third-person perspective and players take control of Joel, while Ellie is controlled by the AI for the majority of the game, although the player switches control in the later sections of the game.
