dm79 has released a demo of the fighting game Hokuto no Ken for the PSP. This is a Lua game that comes packed with the Lua Player, so all you need to do is copy the two folders within the file to your PSPGAME folder on your memstick. There is only one fighting player available at the moment but hopefully more will be added in later versions. Here are the controls:

X: Attack
Square: Jump
Press X in air for airkick