Since there is a "hackathon" being run over this weekend, and the "game" won't be devised until after this weekend, with a launch date of Summer 2013, I think we'll have to wait and see what the "game" will ultimately use on your smartfone.
I'd expect that the app will run in the background tasks, so using the idle time of the smarthpone's CPU, but as I said, we'll have to wait and see.