Nice game! It's pretty big; you've got 5 unique levels and a shop with five items. The gameplay could be better though. There's not a whole lot of gravity, which makes the game feel less weighty. The camera's zoomed in unless you press a button or move your mouse to the edge of the screen, which feels uncomfortable. And there could be more feedback-- things like sound effects or visuals for when the player does something or something else happens in the game. Try it, it makes the game feel good! I think you've got an interesting idea. A game where you fight one boss and gain coins to buy and use stuff to defeat a harder boss. I kind of like it!