In the original Just Cause 2 there was no multiplayer. This did not suit the two fans of the game Jaxm and Trix, who were engaged in mods for it. By joining forces, they developed their version of multiplayer. Later they were joined by other modders. The project was so successful that after the release it was recognized by game developers officially as the add-on and was officially added to all sold copies of Just Cause 2 on Steam as a free add-on. Mod also supports the achievements and the possibility of simultaneously playing several hundred players on one map at once. Pirated copies of the game are not supported.

As in the original game, the action takes place on the tropical island of Panau. In multiplayer, players arrange the chaos using the elaborated game physics and grappling hook. The capabilities of the players and variety of the game modes differ from server to server: for example, on some you can unite in groupings, buy real estate and make raids on enemy gangs. Also available races, Derby, Tron game and other game modes.