Hey Humane Tiger,
Thank you so much for commenting, I really appreciate your advice as this is my first game jam submission and would never have known this was an issue. I've just updated the itch game page with "Windows" selected as the build by following the solution in the URL you kindly provided. I didn't actually know itch had an app until you mentioned it, I'll test through the app too in the future. I tested the download in my web browser thinking everything was all good but know about the itch app now.
I'll follow your suggestion and build for WebGL instead for my next game jam.
I noticed you submitted your game 9 Dayz to the same game jam so checked it out. Ended up playing for 20 minutes and it makes my game look terrible in comparison lol. Awesome work on your game! It's so crisp, the animations are also very nice, has a cool art style and the game is really fun to play. The game details on the 9 Dayz itch page say it was made in HTML5? That's crazy, do you use any type of game engine or framework?