Dark Light Battles was an entry for the 2005 Speedhack competition on Allegro.cc.
It's written by Richard Phipps.
This is that game, but rewritten to use SDL and run on a GP2X.
Source and binaries (WinXP and GP2X F100) included.
http://www.gp2x.de/cgi-bin/cfiles.cgi?0,0,0,0,29,2457