All Purpose Apocalyptic Upgrade System

Story:

Survival in a zombie-infested world is challenging, but I have now acquired an all-purpose post-apocalyptic upgrading system. This is what? You can acquire upgrade points that you can use to upgrade anything by killing the undead and performing chores. With this, I no longer worry a lack of worldly possessions; all I have to do is keep improving. From broken firearms to plasma explosive weaponry, from peas to super zombie-killers, and from paper aircraft to F22s, anything from fruit cores to trees that live for millennia. A single individual is comparable to a whole city in this system!