I love the artistic choices you made in creating this game. I like the approach of no tutorial, making the player discover as they play. It might seem a little slow at first but after the first upgrade it does pick up speed. The collection aspect is a nice touch!
The art style is splendid. I highly recommend people download this and give it a try!
My recommendation would be to attempt a WebGL build so more players will get to play the game. It does require some sacrifices regarding performance but I'm sure you can do it!
Very well done!