I put together a video here (4MB, DivX 5.11) and you can download the initial version here (v1.0 PSPs only ofcourse).
In the demo you can't die yet (disabled for debugging) and there is at least one bug I know of (though nothing serious), you can kill enemies though for score, each time you reach a score mod 10 you'll go up a difficulty (up to difficulty 9).
Hope you enjoy it. I aim to add some more touches over the next few days and hopefully have a src release tomorrow.
Alas it's hard to take a good picture, so I present you with a bad one:
![Image](http://www.tychom.org/PSP/demo_2.jpg)