I really like visuals of this game: textures, esthetic, pixel art. But character design is too simple :(
Gameplay is nice, but I think the game is too short and a bit monotonous.
Sounds and music... Maybe its some bug, but but I had neither. You can find some sound effects just by searching them in the Internet, they're usually free to use.
Also I recommend you to make some menus, like: pause menu, main menu, restart menu, achievements etc.
Don't forget to put some hints, text etc.
Anyways, thanks you for nice ~10 minutes and some insipiration. Wish you luck in future :D