Cooperative (Coop)/co-operative (Co-op) is a group of people who voluntarily work together in coalitions to achieve mutual goals, objectives, or tasks typically against one or more AI opponents. Some enforcement of behavior may be possible. Players may assist one another in many ways: passing weapons or items, healing, providing covering fire in a firefight, and performing cooperative maneuvers such as boosting a teammate up and over obstacles.
In its most simple form, cooperative gameplay modifies the single player mode of a game, allowing additional players, and increasing the difficulty level to compensate for the additional players. Co-op gaming can operate either locally—with players sharing input devices or using multiple controllers connected to a single console—or over a network, with co-op players joining an existing game running on a game server via a local area networks or wide area networks.