I'd like it if instead of just deleting the Balls you have you could sell them back at 50% what you bought them for so you could get something back instead of losing the ball and 100% of the money invested in it.
So as a Suggestion to an Update for later.. Limiting Goblin Sprites to around 100 as well as option to turn off Potion Casting animation Cause Those two make the game lag like nuts.