Overview
For those who don’t know how to get 100%.
Any number of kills achievement
Just kill 100 zombies and you will be done.
Images achievement
At the home screen press Gallary , there you will find some pictures (you may have to play for a while before they appear)
click every image and you will get the achievements.
Tip for kills
Go to the broke and sideways piece of road, jump on it and wait till they come.
Screenshot here –> 