The game is simple and fun. Thanks!
Here is some thought when I play the game:
Spawn Time and Balls On Screen could be traps because the more you invest the easier you miss a ball.
Meanwhile, level 2-4 & 6-9 are harder level without any reward. we enter them only because "it is part of the journey".
Instead of ball HP, it might make sense if we get shorter Spawn Time and more Balls On Screen when we go to higher level. So that the higher level is more difficult but better for farming at the same time.