It is really amazing at the progress iPhone gaming is making with recent updates made to a number of games. The biggest shift I have seen in wow factor however, had to be with the Unreal engine .
According to Anadtech, there is a demo available of Unreal Tournament. Sadly though it requires OpenGL ES 2.0, which translates into the game not running on older iPhones, one must own a 3GS.
I think the biggest downside to all of this however, is that the Unreal Development Kit remains Windows only – nothing is ready yet for the iPhone. Obviously logic dictates that this will change sooner rather than later, but when?