Another game that would surely do without multiplayer mode now gets this donated. PSM3 Magazine confirmed this that Batman: Arkham City will also have multiplayer mode. They claims "Multiplayer is a certainty, but no details on this yet".
Details of which we have not yet revealed, but it is hoped soon to experience more of it .
There are also new rumors that Catwoman as playable co-op partner and Robin will be represented by Nightwing in the game. The PAX event, and the Tokyo Game Show are coming soon, so we can expect some announcements about it.