I think there should be hotkeys for upgrades. It's annoying when I have the perfect height figured out for the fastest shooting, and then I have to move my mouse over to the top to upgrade my damage/max shots. and also add a special upgrade that turns your snowballs into that sack that resembles a penguin.
Every time I crushed one of those giant fruit things, I felt like I was killing part of my character's mind. Naturally, I proceeded to destroy them all.
Don't bother, I think I hear the message already. It's not like I can change it under a day, give me time to rework the game please.