As someone who played this game from very long time, i can say it's extremely difficult for players whom not wanna pay money from their wallet. It's difficult because: Without the premium tanks and premium acc you'll not be able to go too far and stuck where you'll have to sell the tanks in your garage and even this won't be enough. You'll also start to lose credits after tier 6-7 even though if you do have decent damage and score from per game. Let's don't even start with those "containers".