You should probably pull down the WebGL build if it doesn't work.
Also wow, the game is way harder than what I expected from the tutorial alone, I couldn't for the life of me complete two of the levels, and the other two that I did both got C. This is a very simple idea on theme and yet it's very effective, I love that you went for the speedrun platformer route instead of puzzle platformer, cuz janky mechanic won't work well in the latter, but it works absolute perfect in the former, well done dude. I hope both my C are the world records so far.