Hearthstone for being the first game in a long while that I have been completely consumed by. Probably my most played game each week all year since end of closed beta. Naxxramus was a well needed refresher with the new cards, though the game could do with a full expansion soon.
Dark Souls II was enthralling start to finish, but haven't been back to check out NG+ or DLC yet.
South Park was a solid experience- short for an RPG, but no filler.
That's probably my top 3. On top of that other games I've thought were great this year would be Luftrausers, Transistor, Octodad, Jazzpunk, 1001 Spikes, and Nidhogg. Definitely a good year for 'indie' games, though none take a top spot for me.