The game is awesome man, but there is only a few things i would like to see changed in the next update!, the points for the zombies should be at least doubled, it takes way to long to get enough money to buy a gun and open the door, if i was to use the gun i would constantly have to buy bullets thus never actually being able to open the first door unless i forget about the gun all together until i get 1000 points to open the door, ive never gotten very far in the game for that reason, i never got to try out the machine gun yet!
As for the game being on the psp, it requires Custom Firmware v4.01 i have, download a program called PSPdisp, which basically lets your psp act as a 2nd monitor to windows, and while i was messing about i found out that you can Bind keyboard and mouse commands to each of the buttons on the psp, so it was fairly easy really just finding the right software was a pain.
but it really is fun to see and play it on the psp.
The only thing i changed on your game was i changed the resolution to psp resolution.
**EDIT** when you think about it, this is exactly how that new console "ONLIVE" is supposed to work
