I'm glad you enjoyed my idols worthy voice!
Knocking back cannonballs is a very cool idea, and would definitely be fun!
I think if I were to make a real game out of it balance would be a big thing to focus on. All the upgrades are actually quite handy, but, need to be gotten at the right time to be useful.
If you got the scale damage and size upgrade many times, you basically become invincible.