The graphics aren't retina right now. But it doesn't look bad at all on the iPhone retina display. Here is a link to an image I grabbed from my iPhone 4 iPhone4 PH Screengrab, I would recommend opening that on your iPhone.
The rest is perfect, being pixel art.
It's not a big problem, but it's noticeble, expecially in the buttons IMHO.
Said that, can't wait to start the campaign with some friends