Looks good. One bug I found though: I have my Firefox window on OSX positioned on the left half of my 2560x1440 screen, and I could complete the first level fin

Looks good. One bug I found though: I have my Firefox window on OSX positioned on the left half of my 2560x1440 screen, and I could complete the first level fine, but when I got in the shop, the screen turned totally black after getting a message about having to buy a sword. When I made the window only a little wider, I could see the shop interface perfectly fine and continue with the game.