Cool game with fun gameplay. More variety with the course could give the game more depth, such as different types of enemies, hazards, or different courses entirely. More item variation in the shop could be cool as well.
Overall, a good game. Very fun. It could use a keybind for leaving the upgrade menus instead of having to click "return" every time. It could also use a bit more explanation to the story. However, the gameplay mechanics and style was really fun.