In Batman: Arkham City, alongside the main campaign mode, there are various missions that you can play as Catwoman, which you activate with the special coupon code included in the game's packaging. Since Catwoman is a character diametrically opposed to Batman, it will take you some time to get used to her whip, speed, and vicious scratches.
In the numerous side missions you are called to complete, you will find yourself rescuing politicians who have fallen into the hands of mobsters, facing the hundreds of challenges from the Riddler, and answering calls in phone booths where you will be asked to take on smaller but equally enjoyable missions, some of which will co-star the psychopath Victor Zsasz. Additionally, in these side missions, you will encounter familiar faces from the Batman universe, such as the dreadful Bane from Arkham Asylum and the ruthless assassin Deadshot.