Gearbox sends gamers back to the Borderlands for a shooter-adventure sequel of high-velocity combat and custom character development. The first-person action plays out in dystopian outpost environments on the original game's planet of Pandora, five years later, as a greedy industrialist called Handsome Jack seeks to weed out the local populace through a series of gladiator matches. Players choose from four new character types, each with three branches of specialized development in the game's RPG-like experience system. Experience comes with kills and quest completions. Expanding on the original game, Borderlands 2's gun system can create millions of different computer-generated weapons, as well as shields and equipment enhancements. Non-player characters are more expressive, and quest outcomes have more influence on the game world. In addition to the dusty, desert settings of the first adventure, the sequel visits a number of new Pandora environments, including the merciless frozen tundra where the revenge-driven plotline begins. Online, over a local network, or in split screen, the game's co-op mode allows a second player to freely join and drop out of a game in session.