Cool, iPhone shooters are really good, specially the cave ones. There are other really good shooters, specially Super Laser, really old school with wonderful 2D pseudo 3D art, you should check it out if you haven't yet, demo is available and if you like the cave games then set the control to relative, it will feels sorta like cave touch control speaking. It plays very well though. Man, I didn't know that was already out, thanks for the heads up.
On the iPhone ad far as shooters goes I wanna try those PCE ports, I downloaded the demo and it feels pretty good but it's hard to tell with the available game. Have you tried that yet?