Interesting and chilling concept. I think this would work really well as a full game in a "proper" engine like Gamemaker, Unity or even Godot, especially if you were able to make it in something that detected what your default browser was and customized the skin based on that. It'd be a good mindfuck at the very least, and it would give you more tools to work with. It'd have to be embedded in browser though, with a default full screen mode - or people would see the .exe at the end of the file. Anyway, I'm rambling - this is cool! and weird! Weird and cool! :D