I'm not a sparrow expert..
But, I'd try just drawing an SPQuad instead of the image, however I suspect you problem is nothing to do with the image and far more likely to be an incompatibility with the GamePlayController and the current version of Sparrow.
I looked at using the GamePlayController a few days ago, but I think its effectively been superseded by the latest AppScaffold code that Daniel released.
Which makes Sparrow as a view controller and hence can be loaded like a normal ViewCOntroller, which is what i think the GamePlayController was intended for.
Try downloading the latest Sparrow from GitHub and take a look at the AppScaffold example to see if it does what you need.
BTW. I'm now using it and, so far it seems to work well.