First, once again thank you for the generosity you keep showering us with, and also for making the giveaways interesting each time.
Now, with such a massive list and the site using infinite scrolling for it instead of pages, not sure that when it stopped it means it actually loaded all or all it can load at once, or maybe all my browser can load at once (sorted by time played, last was The Falconeer, but of course with all but the first bunch being at zero, the rest may sort differently for others, no idea how that works). Either way, out of what I saw, since it'd have been way too difficult to pick otherwise and I'd have ended up with something like babark's list while you said one game and actually mean to play those games, I decided to eliminate the classics, or at least those I see as such, and any other game I considered that has already been mentioned.
So I'll go with
The Bard's Tale (2004). The fact that it was ported from consoles, keeping the console controls and save points, is quite a problem, as is the dialogue system with just the snarky or nice options, no telling what would be said, and snarky usually being the advantageous option, but it's just wickedly fun thanks to the narrator and the songs and how it pokes fun at the trappings of so many other games. I mean,
come on :))
But now that I picked one, I'd also mention two more I was considering which also haven't been mentioned, and those are Evil Islands and Divine Divinity. Evil Islands
for the crafting system, which for me pretty much made it worth it, and I also liked the character development system, but do play on novice if you do try it, normal is just impossible, and it takes very, very careful playing and a lot of saving and loading. Divine Divinity is basically
ARPG done right (or Diablo 2 done right if you want), again very free character development and a world that's actually interesting and offers reasons to wander around and explore besides the regular hacking and slashing fare, and of course it has the Larian touch.
PS: Out of what was already mentioned, adding another clear vote for King's Bounty: The Legend and Vampire: The Masquerade: Bloodlines. Also for Gothic 2, Sid Meier's Pirates! (2004) and Star Wars: Knights of the Old Republic, but with some caveats, for Gothic 2 I'd like it to stay without the add-on because that makes it too hard, Pirates! is great for a while but can become repetitive eventually, and I prefer the second KotOR (which wasn't mentioned), despite the rushed ending. May also add a vote for Morrowind, but hesitant, because it's great until you more or less manage to explore the world, and has truly memorable moments, but after a while you (or at least I) just stop caring, and eventually stop playing in my case.