Solid game, gameplay is great and the post-game is a lovely feature too. I like that you can control the sound, which gets more important as the game progresses. I think audio could be improved upon, maybe some background music? Also when you select an upgrade that you can't purchase, it would be cool to have a sound effect different from the usual one which could tell the player "hey, you can't buy this right now", and maybe a sound effect for coin collection too.
Overall tho, this slaps B)