I found this in the wikipedia:
"An action game, titled Attack on Titan: The Wings of Counterattack (進撃の巨人 ~反撃の翼~ Shingeki no Kyojin: Hangeki no Tsubasa?), is in development by Spike Chunsoft for the Nintendo 3DS for release in 2013."
Maybe that helps?
Greetings
Kurokuma
