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 Sure do think that War Thunder is surpassing these games in many genres Including graphics, fun for the player, And it even gives you so many options without downloading the other games.