HL2 is not free: https://store.steampowered.com/app/220/HalfLife_2/
It was available for free as part of its 20th anniversary update: https://overclock3d.net/news/software/half-life-2-is-availab...
alt Hacker News
It was available for free as part of its 20th anniversary update: https://overclock3d.net/news/software/half-life-2-is-availab...