This app is called Hero Trainer. It tracks your steps either connecting to Google Fit or Fitbit. As you complete certain walking goals, you earn credits that can be used for DLC, Steam Gift Cards, access to a virtual personal trainer, and of course coupon codes for their apparel (Advertisement for them that you have to pay for, GROSS!). 

The app does have a bunch of cool features that make walking a game.  Typical Gamification techniques, like a leaderboard, quests, and you can also join a Guild. If you are one of the ones, that try to meet a number of steps a day this might be a good app to download to earn some free games. 

Here is the link to the site to check it out: https://herotrainer.io/ 

If you do decide to join, please use my referral code: BON7