Team Fortress 2 is a team-based first-person shooter developed by Valve Corporation. Like its predecessors, Team Fortress 2 is focused around two opposing teams competing for an objective. These teams, Reliable Excavation & Demolition (RED) and Builders League United (BLU), are meant to represent two holding corporations that between them secretly control every government on the planet. Players can choose to play as one of nine classes in these teams, each with his own unique strengths and weaknesses. Although the abilities of a number of classes have changed from earlier Team Fortress incarnations, the basic elements of each class have remained.