Zombie Tycoon

Zombie Tycoon is a PlayStation Portable game that puts the player in charge of their very own undead horde. Contrary to most games who asks you to clear out a zombie menace, here you manage the zombies by using a mix of action and strategy. Created by Frima Studio, it was released for Halloween 2009 and uses the Vicious Engine. Source: Wikipedia, Zombie Tycoon, available under the CC-BY-SA License.