Not sure if it's just me but I've tried to play it in two different browsers, and it just didn't finish loading, so I downloaded the windows EXE and had an error message when opening it.
I had the same problem and the windows download looked to only be the pack - maybe you can work with the helper.gg bot on discord to fix the files?
Download the PCK file too, make sure it's in the same folder. I forgot to embed it.