2013 - Landmark Year?
Bioshock Infinite and The Last of Us are surely frontrunners for Game of the Year - and I am sure we will be revisiting this discussion again once GTAV releases in September.
FFVII, Metal Gear Solid, and of course GTAIII (and of course there are older examples) did a lot to advance the medium past its game/toy/kid misconception. We have multiple franchises (some being decades old now) and titles that are mature for more than just gore/blood (Doom, Mortal Kombat)*
I am seeing a seismic shift in publications like the New York Times - its looking more and more like mainstream media are treating videogames like a valid entertainment medium on a more consistent basis.
It is very possible that at least 3 of the top 5 games will be Mature Rated**
*Not discounting DOOM, and MK as being gory just for being gory/gimmicky - those games were tentpole in their genres and deservedly so.
**Not that there is anything wrong with a Forza or a Mario game making the list; much in the same way I don't think WALL-E or War Horse is any less deserving of critical praise.