Silencer was a multiplayer-only video game released by Mind Control Software for online play using World Opponent Network technology. It combines elements of sidescroller games with other Sci-Fi action games such as Crusader: No Remorse. In the game, there are multiple competing agencies that send agents into the field to hack public computer terminals, with the goal of exposing the Martian government's secrets. Agents in the same agency could work as a team, and agents could buy a variety of items and weapons to help their team excel or to hinder an opponent.
In May 2001, the game was pulled from online play when Won.net went offline.
On September 17, 2007, Arsia Mons, a veteran group who has reversed engineered the software, released an installer that allowed easy playability. The server binaries were unstable and required bug fixing. The lobby servers were completely taken offline shortly after.