The game window resizes weirdly in a desktop browser, it's vertically stretched and sticks to the top-left corner in full-screen. Buttons at the bottom of the level select don't seem to do anything when clicked.
The game itself works fine but I found the levels quite easy. There were a couple near the end where I had to think, but most felt trivial to solve. They often have unused space and random-seeming box/goal placement so it seems like they could be refined a bit more.
(Not sure why this is tagged as idle.)