Geneforge 1: At 28h, this was a bit shorter than expected (I've heard people say that it is 50h+). It was an enjoyable game though, with a very interesting setting, good writing and a fun turnbased combat system.
That being said, it was not a perfect game. The difficulty curve was all over the place, in some areas enemies that gave me no experienced (because of my high level) could give me serious issues, and in other areas I would get plenty of experience for each kill, and I would just breeze through the entire area.

Two games:
- Digital: A Love Story
- Analog: A Hate Story

The first one was better according to me although a bit clumsy (long call distances anyone). Nice stories...

I have such fond memories of playing through Digital! Can't wait to get into Analogue even though it's quite different I guess. I wish there could be some sort of sequel even if it is spiritual to Digital: A Love Story e.g set in say and IRC network or a MUD/MMO.

Sleeping Dogs

Complete List

Recentlly:

Jedi Knight - Mysteries of the Sith

Still a rock solid addon. Took me longer to beat than the main game.

Back to the Future - all five episodes

Probably a better sequel than a fourth movie could have been. Pretty simple puzzles, but all in all very enjoyable.

Half-Life

With the recent announcement of Black Mesa's release, I just had to go back and play this again. Still a great shooter!

Don't know. The only mods I used back in the day were community addon campaigns like They Hunger.

According to http://www.patches-scrolls.de/, the last non-Steam patch for the base Half-life game was apparently 1.1.1.0. There's also a standalone 1.1.2.0 patch, but I am unsure if it already requires Steam.

Also I don't know what the 4.x.x.x patches are, apparently only if you wanted to run a Half-life multiplayer server?

I guess you could _also_ register the game on Steam, but if it is a second-hand game, then it is probably already attached to someone else's Steam account, so the only option to play it is outside Steam, I guess.

(So just to be clear, the original non-Steam retail version of Half-life can be activated also on Steam of course, but only once naturally.)

Slightly off topic, but register your CD-key on steam. It will give you HL 1, Opposing Forces, Blue Shift and the more popular mods (Day of Defeat, Deathmatch Classic, Team Fortress Classic and some other that I've forgot). You can also do this with Gunman Chronicles (you won't get Gunman, but you will get all the HL games), and probably also the HL expansions.

AFnord, I tried that soon after I got it. Turns out it has already been redeemed. There _is_ an old Team Fortress Classic CD I saw in there as well. Might have to try and snag that one ;-)

Darksiders 2 (PC)

Got all collectibles but a single Boatsman's Coin. Oh, well.

Fun game, but I think I might prefer the Zelda-like style of the first game more. Also, not particularly longer than the first game. After the second overworld the story takes over and the third and fourth overworlds are mere dungeon hubs, with the fourth being little more than a small dungeon itself. There is no "final dungeon" and the last boss is a joke. The ending is another of those story-light two-minute cutscenes that usually pass as dénouements in video games. What happened? I thought the idea was to improve production values after the success of the first game?

Still, the game was a blast. I don't regret buying it for full price on minute. Don't think I can be bothered to finish New Game+, though. Same with the Crucible. One thing I don't recall being mentioned about this game was the great soundtrack (although I will confess I normally just check GameSpot's review and the score aggregate they have as I find they usually reflect my tastes well).

Now, if the previous game was Zelda (War), and this was Prince of Persia (Death), what does that make Darksiders 3 and 4? Metroid (Strife) and... Bayonetta? (Fury)

Adding Blue Shift to the list (not a biggie, considering how short it is), now working on Opposing Forces to complete my pre-hyped-for-Black-Mesa playthroughs.

Finished:

Deponia, Beyond Divinity (after 2 years) and Aveyond: Gates Of Night, Aveyond: The Darkthrop Prophecy

Trying to finish now:

Inquisitor, Stonekeep and Imperial Glory

Waiting for:

Empire Earth 4, Deponia 2 and the new Aveyond episode

I finished Xenus 2: White Gold today.

Added it to my list for 2012:
http://www.gog.com/en/forum/general/games_finished_in_2012_1/post796

Mirror's Edge