Let's celebrate the end of the decade by picking the best game in their respective year, starting with 2010.
Note: I decided to only add the top 14 games according to Metacritic for the sake of not making a massive poll - unless the user score is below 70, but you're free to mark the, "other" option and say your reasoning here. Also, excluding ports or an updated version, example Super Street Fighter 4.
My personal pick is Mass Effect 2. The way the game highly improved from the first was stunning, especially the story and presentation.