I like the concept for this game a lot! I found the art style to be very attractive as well.
My recommendation if you wish to go forward with the game would be to either add some form of abilities (like jumping over rocks once every 10/20 seconds) or different zones (say when you reach 2000) that, once you reach them, gives you a minor speed boost and changes the color pallet slightly (so instead of purples and greens, like blues and greens, slowly shifting until you reach the reds).
I think the art style fits the concept extremely well and would love to see more of that style in general. Thanks for making such a cute game and I hope you have a lovely day!