This game is definitely interesting in concept and gave me an idea for something I might want to do in a future jam. I think the greatest flaw of this game is that you have no incentive to go fast. Going slow means you can collect every coin, kill every enemy, and take no damage. Going fast is dangerous and unrewarding. If you plan to go further with this idea, I strongly recommend adding a reward factor for speed. I think it'd spice up the game a lot!