Thanks for playing it, managed to watch the VOD this morning and it was the first time seeing someone else going through the levels, always something to learn. I guess I made the embedded WebGL window a bit smaller at around 700x400, but there was a fullscreen button that upscaled it to whatever resolution you had, I'll try modifying the starting size see if anything breaks.
edit: Yeah, unfortunately if I resize the embedded window on the game page the game doesn't also resize so I guess I exported it fixed at that resolution with only a fullscreen option :(