1. Europa Universalis IV; My most played game this year (outside of TF2). I never had this much fun trying to manage my empire, expand while fighting others to standstill, overcome great odds due to well-placed alliance, and more.
2. XCOM: Enemy Within; Another damn fun one, with lots of new contents added in, diversifying my gears considerably. EXALT is a bit weakly implemented, but still does have some fun moments.
3. Papers, Please; Put it basically, probably the best game with integration between story and gameplay I've ever seen.
4. Metro: Last Light; I don't get why people like Bioshock Infinite so much, because I think that Metro LL is much better. While its story isn't THAT great, it has much MUCH better immersion to me. Improved stealth helps loads.
5: Divinity: Dragon Commander; RTS side is a bit weak, due to the fact that you just need to spam LOTS of units, but the dragon mode and the witty writing helps alleviate that a lot. Need to see more game this ambitious, really.
6: Rising Storm; When I played multiplayer FPS, I never feel as helpless in other games as in Rising Storm (or Red Orchestra 2), period. Consider that it's supposed to be more realistic FPS than others? That's definitely a GOOD thing. Also flamethrowers, can't forget the GLORIOUS flamethrowers.
7: Hate+; It's not as great as Analogue, and I can see the twist coming LONG before it's revealed (probably even before the game's released, even), but you know what, I still like it. The writing's still awesome, it expands a lot more into the world, and the harem route is just hilarious.
8: Sang-Froid: Tales of Werewolves; A bit of a surprise hit, really. Eventually bought it after seeing TB's video, and it's pretty darn awesome. 19th century Canada isn't common setting, the game's much harder (in a good way) than what I thought initially, and unlike something similar like Orcs Must Die, it actually makes the combat pretty tense.
9: Sonic & All-Stars Racing Transformed; A little surprised I actually like this, but I did. Lots of fun, and also hard as nails. I think we need more kart racing games on PC.
10: One Way Heroics; Yeah it's roguelike, yeah it looks simple, yeah it looks like it's from RPG Maker (though it's actually a different one, I think it's forked?)...but you know what? It's fun, it's DARN fun. Lots of customization, unlocks, and multiple endings. Several hilarious dialogues, and ability to carry items to future games. It's really fun.
x: Don't Starve; Fun survival game, with some funny, weird elements in. Shame that there's quite a bit of punishment mechanic for doing too many of the same though (turkey eating berries if you harvest too much, Krampus coming if you kill too many rabbits/birds, etc)
x: Agarest: Generations of War; Yeah, I like it. Bite me. There's not that many Japanese SRPG on PC and I really savor any that's available.
x: Toki Tori 2+; Quite different from original game, but I love the fact that you now interact with environment with sounds. Quite fun puzzles, cute graphics, good music, and tells simple story through only visuals.
x: Tomb Raider; Surprising amount of fun actually, though I don't know about paying full bucks on it (got from Amazon).
x: War of the Human Tanks; Pretty darn fun doujin RTS..ish game that has big emphasis on scouting and one-hit kill. Also dem chibi.
x: Risk of Rain; Also another fun one. Hard as nails, the concept of time vs difficulty is cool, awesome gameplay. Just need randomized levels.
x: Wargame: AirLand Battle; another awesome Eugen RTS...nearly forgotten by most.
Most disappointing:
* Bioshock Infinite; I wasn't hyped before playing it...and as it turns out, is a good reason: meh combat, okay story, linear as frack without immersion that got me for Metro LL, setting so underutilized I question why did they even bother make them detailed, and compared to Bioshock it's just not great (and I do find several faults with Bioshock, so this is even worse). Awesome art and design, though.
* X: Rebirth; Egosoft, I am disappoint. I was so hyped up for this game that the release...ouch. Bad performance, no automation for various stuff, the on foot section is not necessary, and probably several more things.
Wait, I'm too late? Darn.