This game is fun and very addictive, the story line is good and finally you can switch characters from Batman to Catwoman and also you have the chance to roam free in Arkham City, but think twice before getting this game as you will need to have a very high CPU and video card if you want to play it on Low or Medium or an even higher CPU and video card and many more changes if you want it to play on High, but from all the technical stuff, this game is awesome! It actually finishes to a 100% and you don't need to complete the Riddler challenges or even the challenges (it is mostly required) on the whole the game is fun and any of those Batman fans, they should really get this game!
This is an exceptionally good game, but there is a problem- it is massively demanding. I could spout off about how awesome my hardware is and how that makes me a better person because I can play this at full detail but I wont. I understand that a lot of PC gamers dont have the kind of hardware required to run this at full detail. So be warned- if you dont have the latest multi GPU and multi core CPU you are going to have to turn quite a lot of stuff off.
As far as the game is concerned though- it is pretty flawless. Arkham Asylum was an absolute triumph and set the bar for all licensed games of the future (so many rely on the identity of the license rather than the game play). This has taken that bar and raised it so high you will need some of Mr Waynes alter egos gadgets to see it- never mind reach it. At the price of 25 pound it is a steal.