It's not pay to win. I've completed adventure and I've not payed 1 cent. you'll get 2 big walls in the game for now it's to slow down progress so that adventure is not to fast. I've played the game for some time and it's still in development and grindy as hell. If you will like to support it I'm not going to stop you but if you're looking to make it more easy you'll need to pay at every wall. At the end of the day it comes down to you pay time or you pay money that's all one you.