If you're looking for a beautiful PC shooter, look no further than Futuremark's Shattered Horizon, a unique multiplayer game now available for download. 

Set in space, Shattered Horizon makes the most of its unique environment; players can use the darkness and the zero-gravity to their advantage in combat.  Of course, being set in space means everything is treated differently than in a conventional shooter -- every tiny detail.  It seems players have been curious about sound, so Futuremark put together a little gameplay demo of the game's "silent running."

This mode allows players to move without any sound, which is completely possible in space, but as Futuremark notes, an FPS becomes more difficult without any audio cues.  As such, the player's suit has an "audio simulation" feature, which recreates sounds based on sensor information taken from one's surroundings.  "Silent running" basically shuts off this feature, letting you move in complete silence for stealth kills, while sacrificing radar, HUD, and maneuverability.  Hey, a perfectly executed punch to the back of your opponent's head is worth it.