After the first tours, you will get points and cash to buy things in the market. There are new upgraded cars and also tools to update your current car's performance, like wheels, engine and so on. After smashing some dirty zombie hordes and get big cash, you can unlock real stuff in this game and became much more stronger.
Like, if you get new Bus, it is faster than old cars and it is possible to complete one level to another.
This version for now is the newest version of Earn to Die 2013. We will upload new versions as they became available for public.
On This website, you can also see other versions of that awesome and cool game. So, try all of them and have fun.