In addition to tearing down walls and thugs' faces, the Batclaw can now be used to grab items. In the demonstration we saw, Batman grabbed a hidden Riddler Trophy from a distance because he was too lazy to walk over to it.
2) Batman Has Super Mario World's Cape
Much like Mario's yellow cape in his 16-bit debut, Batman can fly long distances by swooping down, catching wind, and gliding back up. We're told that you can fly through all of Arkham City without ever touching the ground.
3) There Are Smoke Bombs
Among Batman's inventory are Smoke Pellets, something that really should have been in the first game. In the demonstration we saw, Batman threw these down at his feet like a magician to "disappear" from the eyes of some of Joker's minions.
4) Catwoman and Two Face Have New Voice Actors
Fans of Batman: The Animated Series may be disappointed to hear that neither Richard "Bull from Night Court" Moll nor Adrienne "That Girl From The Fog" Barbeau will be reprising their roles as Two-Face and Catwoman, respectively. Interestingly, Barbeau was in Arkham Asylum, as one of the asylum physicians Batman rescues.
5) ...And So Does Harley Quinn
Surprisingly, Arleen Sorkin did not provide the voice for Harley Quinn in the demo we saw, despite being in Arkham Asylum. When pressed, we were given a stone cold "no comment" on whether this would be true in the final game. The actress we heard was a pretty good imitation, but obviously not the real thing.
6) Alfred Replaces Oracle
In Arkham Asylum, Batman was in constant radio contact with The Oracle, who was able to monitor his situation and provide remote help. In the demo we saw of Arkham City, this role was being fulfilled by Batman's faithful butler, Alfred.
7) Calendar Man Knows What Day It Is
Not only is series villain Calendar Man confirmed to be in the game, he's also got some unique dialog during most major holidays. Play the game on St. Patrick's Day, for example, and he'll tell you all about a murder he committed on that day in history.
8) Bad Guys Can Take Hostages
There was one scene in Arkham Asylum where Mr. Zsasz took one of the doctor's hostage, in a scripted event that forced players to batarang his face. In Arkham City, the average grunt can do this contextually, providing a new challenge for Batman: if the hostage dies, it's game over.
9) Forget Double Takedown, There's a Triple Now
Those of us who have kept up with Arkham City previews probably knew about Batman's ability to counter two bad guy sat the same time, but we can now confirm that there is a triple takedown too. We didn't get to see it, but we're told it's "awesome."
10) Weapons Are Highlighted in Detective Mode
Just like in Arkham Asylum, baddies holding guns appear red in Detective Mode. New to Arkham City, however, is that melee weapons are now clearly visible. It's easy to tell if a guy is holding a pipe, as that pipe will appear as a visually striking yellow.