Few things:
1. Make the game clear the screen when you are buying lives, because at the current state often it is completely pointless - you lose lives instantly after you go back to the game.
2. You write a lot about what you have done while creating the game, but there is no description of the game itself and this is the most important. For example - what are the darts for?
3. The slowing down seems to be not working, I already bought 2 upgrades of this and the balloons did not slow down. Or it is being activated in some way? Again - no description.