CNN goes into a little more detail into the mechanics of the game. I just downloaded the app, but don't have much time right now to play around with it. It's apparently non-partisan, but Obama seems to be winning, that's because:
"The game becomes more than just a single-player fight between Obama and Romney," Mustard said. "There's this cool metagame where millions of people around the country will be playing the game and earning votes. If you're actually voting for Obama, then you'll likely be playing as him in the game. So we'll have this running tally of who's winning the election, at least in terms of battling it out in this cool new game."
It's also tied in to Rock The Vote, which was definitely very partisan the last time around.