I think the only game I've bought and completed this year was Bioshock: Infinite.
Best games I've played this year mostly were released before. Skullgirls has been tons of fun, To The Moon is by far the best story I've ever experienced in any media, but techinically both were released in 2012. Some of the games in the Origin Bundle like Crysis 2 was tons of fun, but that was a 2011 game.
Infinite wins by default.
EDIT: Oh, I did play Metro: Last Light. A big improvement on Metro 2033, but I really disliked some changes they did -- streamlining gas masks and certain gunplay when I thought they were perfect in their awkward state in 2033, featuring Day One DLC including Ranger Mode, and completely ballsing up characters like Anna, Khan, and Ulman. Infinite still wins, even though I might've sunk more time into Last Light.