I couldn't figure out level 4 but I'm pretty sure that's a me problem lol
Very creative idea with the different shapes having different abilities, fun sound effects and graphics, useful tutorial, and nice music!
My only suggestions are to make the menu more accessible by giving more options to control them (eg on the main menu, the mouse can change what item is selected by hovering but it can't actually use the buttons? Like I had to press enter to play) and to prevent the arrow buttons from scrolling the page. I don't know what you used to make the game, but if you did it in JavaScript a simple "e.preventDefault()" would work (although unfortunately they would still scroll until someone interacted with the game, but that's a problem on itch's end, not yours)