This is a fun game and impressive for a three-day jam. I found it because I also just completed a jam, VimJam2, and I'm going through some game updates to publish an update before they announce the results Monday.
I searched for games that play in browser and were made with GameMaker Studio. Can I ask how you handled your game size? My executables will go full screen and maintain their aspect ration, but I can not figure out how to make HTML work in full screen switching. And I can't find documentation either.
Your game isn't fullscreen, but it's nice and large. Did you upscale every single sprite and the room in GMS before exporting, because I've thought of that, but it seems like a lot of work when there has to be a better solution.
I'd appreciate any feedback or help. Thank you, and again, great game.