>>414513616
For Half-Life 2, use this
https://store.steampowered.com/app/658920/HalfLife_2_VR_Mod/
Don't know of any way to do Black Mesa in VR, but there's a mod for the original version here.
https://store.steampowered.com/app/1908720/HalfLife_VR_Mod/