Yes unresponsive. The music continues, but the button gets clicked and freezes. Here is a screenshot. This happens with My Pals and Pal TV too. I just tried in Edge and it worked... So it seems to be a Firefox issue. I'll restart my computer just in case there's a weird memory leak happening with my 50 tabs of Unity Docs and forums open.
Edit: Still happening after a restart, looks like a Firefox issue. Played it on Edge and the game was fun! It has great bones but not much content. I could see a full release out of this with lots of interesting mechanics added.