NOBODY has knocked Batman: Arkham Asylum for any of it's accomplishments. Maybe, the only complaint can be that the detective vision was used more than it should have been. Causing players to go through the game in x-ray mode where everything is see though and trippy colors. That minor gripe is a speck on the ever impressive B:AA. 
Now, before the sequel comes out and details trickling in, breakthrough news comes in...from the original game. GameInformer reveals a secret in Batman: Arkham Asylum that foretold the coming of Jesus...sorry, Batman: Arkham City. A game based around secrets and finding them out, and no one thought to mess around in Warden Sharp's office? Just goes to prove how satisfactory Batman: Arkham Asylum is. Rocksteady and Batman are the Watchmen and Ozymandias of the game world.