Our goal is to support all Apple devices, but unfortunatelly, the full support will come later after the release. The challenge is to get a smooth framerate on iPhone 2G while having a great game for iPhone 4. So, we are giving full support for 2G to 3GS for the release date, then we will bring retina display support and iPad.
To achieve the best looking game possible we are working hard on textures and lighting. But we want a high framerate because this is a fast action game, so it's a full time fight between high res textures and script optimization.