Batman: Arkham City
Ico
Dark Souls
The entire MGS series (not including Portable Ops or Peace Walker)
Pikmin 2
Red Dead Redemption
Shadow of the Colossus
The Walking Dead

I went through my list of games just now and updated the ones that I know I finished in 2012 so they show that information. Some of the games I'm not sure whether I finished early this year or last year, so I didn't include those, but I finished the following games in 2012:

Dead Island. (PC)
Flight of the Amazon Queen. (PC)
Ghost Recon. (PC)
Resident Evil Classic. (Nintendo DS.)
Super Mario 3D Land. (Nintendo 3DS.)
The Walking Dead. (PC.)
The Witcher: Enhanced Edition. (PC)
Zelda: Ocarina of Time regular. (3DS)

I started keeping track of this because it annoys me that I have such a huge backlog, so I use the amount of games finished -1 in year X as the cap for how many games I can purchase in game Y. In other words, since I finished 8 games in 2012 I get to buy 7 games in 2013. (Gift purchases excluded.) That way my backlog is always shrinking, AND I limit the amount of money spent on games. :)

2013:
Deadlight - AMAZING GAME ! It's almost a movie.

Post here: http://www.gog.com/forum/general/games_finished_in_2013

This is something like a 'delay' of the year. Like when you forget to write the right year on a paper...lol.
tks for remember.

McPixel.....bad/grinding game. =\

Bioshock
Bioshock 2
Still Life (from GOG)
X - Beyond the Frontier
The Elder Scrolls IV - Oblivion (GOTY) after 400+ hours of gametime...

This is what I could dig out from the cobwebs of my memories of 2012... in no particular order:

Elder Scrolls IV: Oblivion GOTY ed.
Halo Reach
Halo 4
Mass Effect 2
Monkey Island: Special Edition
Monkey Island 2: LeChuck's Revenge SE
Tales of Monkey Island
The Walking Dead
Law and Order: Legacies
Sam & Max Seasons 1-3
Strongbad's CGFAP
Back to the Future [Telltale Games]
Jurassic Park [TTG]
Hector: Badge of Carnage
Puzzle Agent 1&2
[Isn't it really obvious that I discovered Telltale Games last year?]
Bioshock II
GTA IV [replay]
Fallout 1&2 [yearly playthrough]
Fallout: New Vegas + DLC
-Lonesome Road
-Dead Money
-Old World Blues LOL
-Honest Hearts
Unepic
Discworld
Discworld II: Mortality Bytes!
Discworld Noir
DeathSpank: Thongs of Virtue
The Legend of Zelda: Skyward Sword
Silent Storm 1&2
Deponia
Portal 1&2
Half Life 2
Another World: High Res Collectors Edition
Metal Dead
Gemini Rue
Resonance
Blackwell Bundle
Emerald City Confidential
Cave Story
Machinarium
Samorost 1&2

Scrapland
True Crime: Streets of L.A.
Far Cry
Under a Killing Moon
Halo: Combat Evolved
Midnight Club II
Mafia
Manhunt
Homeworld 2
Star Wars: Battlefront
Portal
Battlefield Vietnam
Rise of Nations: Thrones and Patriots
The Elder Scrolls III: Tribunal
The Elder Scrolls III: Bloodmoon
The Pandora Directive
Fallout Tactics
L.A. Noire: The Complete Edition
Pokémon FireRed
Tex Murphy: Overseer
Outcast
Pokémon Ruby
Summoner
Crusader: No Remorse
Aliens versus Predator Gold Edition
Shogo: Mobile Armor Division
Roberta Williams' Phantasmagoria
Dune 2000
Commandos: Beyond the Call of Duty
The Operative: No One Lives Forever