The mechanics are easy to get while playing the first 2 level! It gets a bit harder as level increases since the enemies are completely randomly spawned so they would be too more and far from each other to be defeated by only 3 balls. And when enemies are hit once, the second time when the ball hit, it would made the ball immediatly stop, so there's no way for me to defeat more than 2 or 3 enemy by 1 hit. Maybe players can get more balls when level increases would make the gameplay better in terms of difficulty curve!