Half-Life: Counter-Strike is a stand-alone package containing a collection of multiplayer Half-Life mods.
Includes: Half-Life Multiplayer, the Counter-Strike mod (play as terrorists or counter-terrorists), Team Fortress Classic, Opposing Force Multiplayer (adds marines and new equipment to Half-Life MP), and some fan-created mods: Wanted, Redemption and Firearms.
The Linux and Macintosh PC versions were never available separately. When they were released, Half-Life: Counter-Strike could only be bought as a compilation pack containing both Counter-Strike: Condition Zero and the original Half-Life: Counter-Strike. However, existing players who only owned Half-Life: Counter-Strike thus received it for the additional platforms for free, even if they did not own the original Counter-Strike: Condition Zero or never bought the compilation pack.