World's Greatest Detective; Worlds Greatest Game
The best analogy I can make is if the film Batman Begins is to Batman: Arkham Asylum the game, then The Dark Knight film is to Arkham City. Arkham Asylum was already one of the best action/adventure games to come out in a long time.
Its mix of exploration, combat, and story telling set a bar that a lot of games have to compete with. Arkham City takes all of these elements and expands upon them in every way. Remember the fun you had playing as Batman? Now you get to play as Batman, Catwoman, and to some extent even Nightwing and Robin. Remember the awesome combat system? Now yiou can do double, even triple counters, you can counter thrown objects, gadgets are more involved in combinations, and enemies now have different types of weapons to make you change your strategies. Remember the Riddlers challenges from the first game? Now they are far much more than a fetch quest, you actually need to use your mind to get some of those elusive Riddler trophies, and they even have more of a take in the overall plot of the game. Even the setting itself has been expanded from the grounds of Arkham Asylum to the entire Northern Section of Gotham City. To use the old cliche, Arkham City is bigger, better, and badder than Arkham Asylum in every way, which is a huge accomplishment.
The story is absolutely fantastic, and it immediately catches your attention from the very beginning. Almost every character from Batman's rogue gallery is utilized in this game in some capacity or another, and from my perspective they all equally contribute to the experience. You get to really understand Batman's resiliency in this game, because you are constantly changing focus from the main story to side missions which all feel important. One moment you are fighting Mr.Freeze (which is one of the best boss fights in a video game ever) the next you are tracking down a serial killer in the streets, then you are trying to figure out how to get those damn Riddler trophies. I guarantee this is game that you will strive to have 100% completion, because everything feels so damn important. You literally want to put all these gotham super villains behind bars again, because you are the god damn Batman.
When you finally finish the main storyline and sidequests, you are challenge even further to beat all of the combat and predator campaigns the game has to offer. Even after beating those there are tons of hidden easter eggs all over Arkham City for you to find, and some of them even tell the story of how everything came to be. Seriously, almost every bit of Batman lore is touched upon here.
If you are a fan of video games, you will love this game. If you are a fan of the Batman franchise, you will love this game. If you are a fan of both, you are going to be locked in your house playing this game nonstop until you have done and found everything. This is by far the Game of the Year for 2011. It is that damn good.