I tested it out but I sadly can't make it possible to be played in the browser. Even the build with reduced texture resolution to fit in itch.io 's limitations was so extremely heavy on the system while being played in the browser that after loading it only played sound but the rendering work at all - the browser issued a message of the website not responding anymore. And this was tested on high-end hardware.
Itch.io itself says on the topic of uploading HTML5 games:
"If your game does not meet the requirements please consider distributing your game as downloadable instead. Very large HTML5 games tend to be a poorer experience compared to the equivalent downloadable in respect to loading time and performance."
Thus I'm sorry to have to inform you that there won't be a browser playable version of my game since it is simply not suited to be a web game.