What a polished gem! This was a simple but fun game, very well presented. I love the implementation of the win condition being just one of the upgrades in your menu. Very sleek. Clever, well done.
I played with the mouse. I respect you implemented keyboard controls to fit the theme, but I did not enjoy playing it that way. That's my only negative comment on an otherwise very well realised game. You did a lot with a little and should be proud!