Batman : Arkham City - Multiplayer Possibility

Game - Batman : Arkham Asylum 2
Publisher - Warner Bros Games
Developer -Rocksteady Studios
Platform - PC, 360, PS3
Release Date - 2011

From PSM3 :

"Multiplayer is a certainty, but no details on this yet"

Visit here for new Batman : Arkham City Screens

Source
http://arkhamcity.co.uk/