1. Divinity: Dragon Commander
Solid Campaigns, Solid RTS gameplay, Solid Graphics, Great AI, and those memorable council meetings... :P Dragon Commander's combination of decent-RTS mechanics with surprisingly entertaining political/RPG elements make it one of the most memorable games of the year- and arguably the best.
2. Call of Juarez: Gunslinger
The Cartel SHOULD have been franchise suicide. And yet the Call of Juarez yet lingers in the ears for good reason. For a budget FPS, Gunslinger is absolutely stellar with outstanding gunplay, an entertaining story mode, and addicting arcade mode.
MotoGP 13 may not have as much content as many of its car-based contemporaries, but still unquestionably serves as a great motorcycle racing simulation for those interested. The fact that the AI is quite good also helps a lot. :P
4. XCOM: Enemy Within
Enemy Within is not just a supurb expansion. It's an avatar of the realization of how entertaining Firaxis' take on XCOM is in its own ways. I still feel Firaxis' take on XCOM doesn't do the old games justice- but Enemy Within made me realize it really doesn't have to.
5. Hero of Many
Easily one of the best mobile games of the year. This is a beautiful and surprisingly engaging game. When applied right- minimalism sometimes really can work. o_o
6. Far Cry 3: Blood Dragon
Even with its bite-sized open world, Blood Dragon offers plenty of value for its price.
Ninjas get to play for free. The surprise spiritual-successor to Dark Sector has extremely solid mechanics to keep you coming back.
8. Hearthstone: Heroes of Warcraft
Arena mode cannot be denied! Hearthstone is already showing potential as an embodiment of something that is simple on the surface, but surprisingly complex at the core.
9. Bionic Dues
Unquestionably the best game Arcen Games has made since AI War. Bionic Dues was probably the most pleasant unexpected surprise of 2013
10. Injustice: Gods Among Us
The antiquated AI is a major buzzkill- but outside of that, Injustice still squeaks onto the list via offerings of plenty of surprisingly accessible content for a fighter.