ReKleSS updated his shooter game for the PSP. PSP Kobo is a port of xKobo. Changes in this release:

New release. The main game screen now takes up the full height of the psp (271 pixels instead of 226), doublesize radar, and analog control. Also, I’ve made a rather poor attempt at an icon… anyone want to provide me with something better? It was uploaded over the old file, so use the same link.

http://forums.ps2dev.org/viewtopic.php?t=2423