EASTER EGG! PRESS THE PERIOD(OR DOT) IN THE LAST BADGE AND IT WILL TAKE YOU TO YOUTUBE VID CALLED "ZOMBIE KID LIKES TURTLES" PRESS + SO EVERYONE CAN SEE IT
after level 25, something will appear in the map
which is level 26:
you have to kill 100 baddies,and no its not a joke and i did it just now.
the best part is when you finish it you will unlock a cheatcode: the silly sound..
i wont tell you what you need to type so you can hear the silly sound.
and there is 2 perks i need to get. and all of my weapons exept chainsaw are already level 6 and they are golden