Zombie Infection 1.1 has been released by Zharikov Vitalik just recently, and the update/changelog isn't the longest after a month and a half, but here's what's new:
"Updated lighting.
Game has a more apocalypse feel with the picture.
Lighting reveals map a few steps ahead of you.
Redrawn zombies that are stronger and more aggressive.
A few zombie A.I are more intelligent.
Added the freedom of action of the character."

http://pspcustomfirmware.com/zombie-infection-1-1.htm