It's been a really long year. There were things you promised yourself you would get done but they slid by the wayside. Maybe your backlog of games is getting a little fat and you want to work some of them out of there. Maybe you want to finally finish some super long game like Skyrim or Assassin's Creed 4: Black Flag. Maybe you want to spend less time playing games and more time with your family.
My gaming resolution this year is to clear out a substantial portion of my gaming backlog on Steam. It's a difficult task actually because the more games I go back and play the more games come out and get added to the list. It's a beautiful and hectic loop.