Really great game design, good job!
I would suggest to show some sort of level-end-screen in-between levels (where you just show the scores so far, maybe with a rating, whatever...) just to interrupt the game pace for a short moment so the player can breath for a short moment (and you, as a game designer, acknowledge the player has made it to this point).
And maybe ramp up this game profile a bit with screenshots, video or gifs. The game deserves more players.