Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
I played this game and I can say its on really good princip and is really good to see how funny this game can be (quests,events and many many more).I think you should check by yourself or write some quality comment about your opinion for this :P.