S.T.A.L.K.E.R.: Clear Sky - S.

Counter-Strike - Counter-Strike is a PC-exclusive FPS video game developed by Valve Corporation.

Insurgency - Take to the streets for intense close quarters combat, where a team's survival depends upon securing crucial strongholds and destroying enemy supply in this multiplayer and cooperative Source Engine based experience.

Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.

Deus Ex: Invisible War - Deus Ex: Invisible War is an Action-Adventure, Role-playing, FPS (First-person Shooter), Science-Fiction, Stealth, Dystopian, Female Protagonist, and Single-player video game developed by Ion Storm and published by Square Enix.

Rage - Rage Software, also Rage Games and FX Digital Network, was a British video game developer.