The Free Games List

Unless you got Portal for free during Valve’s promotion, you’re going to have to buy a Source game in order to play the many mods available.

Here’s a list of what counts as a Source game:

(This list may change – see this link for the latest titles)

Left 4 Dead 2
Half-Life 2
Team Fortress 2
Counter-Strike: Source
Portal
Half-Life 2: Episode Two
Left 4 Dead
Half-Life 2: Episode One
The Orange Box
Day of Defeat: Source
Half-Life 2: Deathmatch
Valve Complete Pack
Counter-Strike Complete
Garry’s Mod + Team Fortress 2
Half-Life 2 Episode Pack
Half-Life Complete
Half-Life 2 Complete
Counter-Strike: Source + Garry’s Mod
Source Multiplayer Pack
Team Fortress Complete