Achievements are earned by completing specific tasks in the app, for example running a specific distance in a week, or picking up a lot of one particular type of supply. If you have a ZombieLink account you can see these in the Achievements area of your account on the website.
Achievements are calculated by taking data from your account on ZombieLink, rather than straight from the app, so they should work with both Zombies, Run! and Zombies, Run! 5k Training.
We won’t tell you how to get a specific achievement in its description because we want you to have fun using the app in different ways in order to discover the various achievements you can be awarded.
Please Note: It's not currently possible to view achievements on the new ZombieLink website. We will be bringing this feature back in a future update.