It would be nice if it was again possible to run it in current Mac OS. The original Half life still lists Mac OS but with incompatible information (newer versions of Steam require recent versions, but HL only runs on old 32 bit OSX)
replies(3):
* I first installed Whisky, a Wine/Game Porting toolkit/app thingy (https://getwhisky.app). Then I installed Steam for Windows inside Whisky, then downloaded HL2. The download was a little bit hiccup-y, but it worked. Testplay of HL2 was great, apart from the mouse.