Sadly seems broken for me as well.
Viewing post in r/Whatcouldgowrong??? jam comments
If you haven't been able to play due to the screen resolution, I haven't fixed this yet but if you zoom out with the browser zoom, then back in to 100% the screen fixes itself. This is required for each level too. Working on a real fix.
If you are unable to play browser version for some other reason please let me know. I am working on fixing the Windows version