Jake's point about demos is a good one. There was a real accountability to them -- the developer had to show you something worth playing before asking for your money. That model has been entirely replaced by refund windows and early access, neither of which is quite the same thing. What I miss...

I'd push back slightly on Half-Life 2 as a definitive all-time pick -- it's an extraordinary technical achievement for its era but the writing is quite thin. Planescape: Torment, Morrowind, Gothic II, Baldur's Gate 2 -- these are the games that actually had something to say. That said, Disco...