Lazrhog has ported the Kenta Cho shoot-'em-up rRootage to iTunes (thanks Kotaku).
The game is free, importantly, but you will have to buy an iPod Touch or an iPhone to play - it's those hidden charges again.
rRootage involves continually shooting at a mother ship while avoiding baddies. Simple. You control the ship with your finger, and activate special powers by tapping the touch-screen with another digit.
Kenta Cho is the boss behind Japanese freeware creator ABA Games. His projects are usually bonkers reinterpretations of retro favourites.
Head over to the ABA Games website to try some of his free work.