Stig79: How many of them have you beaten?
Old games, I really can't say, it would be impossible to remember them all, starting from the Commodore 64 days back in the 80's. :)
GOG games, not that many, less than a dozen, I think, mostly small games. A few adventure games that I knew well from the old days (the Kyrandia series), no challenge there but still fun. A few more recent adventure games which I had not played before, Another World and BG1EE with the SoD expansion. The game I beat most recently was Thimbleweed Park, which was kindly donated by a generous GOG user. That's what I've completed since I joined GOG in late October.
I also played Alpha Centaury, got my ass kicked a couple of times (I wasn't any better back in the day) and put it aside to play other things, lol. Played a few campaign scenarios from Star Wars Galactic Battlegrounds, but got bored before completing them all. And played for a while Warlords Battlecry 1, I'll return to it eventually to complete the campaign.