GLACIALHELL
CAGiversary!
Go here: https://gamesrepublic.com/ Register , and after registering they will give you this game. Go to your games, press download and select the last option, this option is the steam key.
Steam codes for Anomaly: Warzone Earth are all used up for now but they will be back. If you registered with the service and only got the DRM-free version, please stay calm - you will get your Steam code eventually.
It's interesting, I didn't get a code, but I have it unlocked on my account. I don't know if I got it from a HumbleBundle before, but did you guys just get it straight on your accounts (and not receive a code)?you will get your Steam code eventually.