I got the same problem Mr Raven mentioned on the Itch page – the game’s framebuffer is larger than the iframe containing it. You could fix this easily the in Itch settings by enabling a fullscreen button, or by setting the correct dimensions there. I ended up working around it by using dev tools to find the iframe and then element.requestFullscreen()ing it.
Once the game gets running, it’s pretty good! If you were to build further on this, it would be cool to have lots of exotic shapes (the airplanes are great), and maybe let the player rotate them somehow? I could see it turning into a complex packing puzzle.
