What may they have let slip out into the wonderful world of the interweb? Well the below bullet points.

Story info:

• Quincy Sharp is now running for mayor.
• Sharp used the Arkham Asylum incident to help win the election
• Sharp took credit for getting the Joker situation under control
• Arkham Asylum and Black Gate Prison are unfit to hold inmates.
• Quincy Sharp buys off part of the slums and walls it off, creating Arkham City.
• Sharp contracted a mercenary group named Tyger, getting them to defend the walls of Arkham City
• Prisoners given one rule: "Don't try to escape"
• The penalty for breaking that rule is death
• A year has passed since Arkham Asylum
• Hugo Strange is in charge of Arkham City.
• Two-Face is admitted into Arkham City
• Two-Face plans to execute Catwoman to gain respect of inmates.
• The overdose of venom may not be what's wrong with the Joker.
• A lot of the super villains have formed gangs, have control of different areas in the city

Game play info:

• Rocksteady is going to try for a highly detailed city
• You are now able to counter two attacks at once.
• You can place explosive gel on the back of an enemy during a fight
• Press a button and Batman will taunt enemies
• Rockstaedy is hoping to use more of the "forensics" angle from the first title, incorporate puzzles in them that will get more complex as you progress
• All gadgets included in the first game are available from the start.
• Batman has his smoke bomb.
• Broadcast analyzer: Mainly used so that Batman can listen to a message from the Joker
• There are several broadcasts Bats can listen to, including the GCPD dispatch and Gotham FM
• Because of Oracle being MIA, Alfred is the one in Bruce's ear
• Interrogations instead of Riddler maps now
• Optional sidestories for some characters, including Zsasz
• Gangs roam Arkham City; these are recorded in Batman's criminal database.
• New costume for Harley
• Rocksteady not talking about multiplayer/co-op plans yet

While not all that detailed, it is a nice little build up for things to come. I do like the fact that you will get to use all of the gadgets from Batman: Arkham Asylum from the start, but I have a feeling that they will go God of War II/III on you at some point. (Read: Taken away to give you a challenge for the rest of the game) That is just my thought process on that.

This also kind of solidifies my thoughts on co-op with Catwoman a bit too. I'm assuming that you will need to swoop in and save her ass before Two-Face "offs" her. It makes sense that would be how they would try to bring in a co-op for all the cry-baby-whiners who think every game needs co-op.

With all that, let's just sit back and see what else the mighty bat-computer will dole out here soon. (Read: The mighty internet and people not wanting to keep everything exclusive before the magazine's publish date.)