Haven't tried the game but it seems to be interesting based from the screenies provided in the official site. The game is made possible by GREE Japan and I have no idea if it will run on Android, iOS or both. The anime has been one of the most talked about in the community and I think that it's popularity will reign supreme among the spring anime line-ups this year. If you haven't watched Shingeki No Kyojin yet then I highly recommend it to you as I've been following the first 4 episodes of the show.
Anyway you can head on to the official site using the link here and see for yourself if you find it interesting. So far it's running on Japanese Language so if you're confident about your language skills then I think you'll enjoy the game especially if you're more of a mobile gamer.