Overwatch is a cooperative asymmetric multiplayer Real-Time Strategy Shooter (FPS/RTS hybrid) powered by the Source engine and set in the Half-Life² universe. It pits a team of rebels playing cooperatively in first-person (the Resistance) against one player who assumes the role of commander to the Combine forces (the Overwatch), controlling units and the environment around them from a bird's-eye view.
Listen to the soundtrack here on this page.
Read more about the mod itself here: https://www.moddb.com/mods/overwatch