The control + W is indeed annoying :/
I think you have a pretty decent game and I like the idea of the delivery while upgrading your balloon. It's pretty fun! But sounds and a better feedback when you're colliding would make it even more enjoyable. Maybe a more far away camera? And allowing the player to rotate the camera around freely?
Also the worm scares the shit out of me everytime he comes by xD he's so fast and comes out of nowhere. I don't know if he's following a set path or not but the way he's movement scares me (in a good way)