|Counter-Strike: Condition Zero||Counter-Strike's first successor. Including Bots, singleplayer gaming and "Deleted Scenes" (something like singleplayer with a story)||1.0|
Half-Life is based on the GoldSrc engine, that has spawned more add-ons that we can count. For example, Team Fortress, Counter-Strike, and Opposing Force just to name a few.
Note: Natively available for Linux.