Don't put money in this game

Nice job! It is indeed possible to clear all levels without spending money! It's totally optional to buy boosters and gold bars 😊

Good advice. I almost deleted the game because I kind of got addicted, and I would spend more than I could afford to get through the levels. It ended up making me dislike the game, so I just have to tolerate being stuck on a level for a week or two at a time.