First Person Shooters are among the most played computer videogames. They combine navigation, interaction and collaboration in3D virtual environments using simple input devices, i.e. mouseand keyboard. In this paper, we study the possibilities broughtby these games for musical interaction. We present the Couacs, acollaborative multiprocess instrument which relies on interactiontechniques used in FPS together with new techniques adding theexpressiveness required for musical interaction. In particular, theFaders For All game mode allows musicians to perform patternbased electronic compositions.