Arkham City held the title of my favorite game of all time for a short while in 2011. A polished, sprawling masterpiece with an impeccable level of detail and a fresh take on Batman that hasn't really been achieved as well since, even by Rocksteady themselves. The freeflow combat system is polished to perfection here and the emphasis on gadgetry and stealth, especially on the higher difficulties, make it a very replayable experience. Tons of content and lots of different ways to play.