The game is 20% player 'skill' and the rest is random dumb luck. It's basically a disguised slot machine. You can fail a level 10x in a row, in one example I used 2 'boosters' and still failed then the next time I played the level beat it easily with no additional help. The game 'rewards' you with discounts on cash shop purchases. Spending your own money isn't a reward. Avoid getting into this game, typical mobile game where your own skill is hamstrung by the developer to push microtransactions.