An unannounced new game from Valve already has more than 10,000 players before the game's launch has even been confirmed by the Steam developer. While more widely known throughout the industry as the creator of one of gaming's most prolific online marketplaces, Valve has a rich history as the studio behind several beloved franchises. Half-Life, Portal, and Left 4 Dead have stood as some of the developer's biggest hits, while others like Team Fortress 2 have persisted as cult classics. Now, the newest game from the studio is already building excitement.