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.
Compared to War Thunder, this game is nothing. War thunder has better graphics, a wider tech tree, etc. The thing that surprises me the most about War Thunder is that tanks are only a fraction of the game, and it's free!