That is weird. You're the second person so far to have encountered this and I have no idea what could be causing it. Could you check the console (F12 to access dev tools on Firefox) to see if there are any errors shown there?
And I have standalone on Steam available for few bucks but that too is just a wrapper app using the same browser version of the game. Porting it to completely native would be a quite a big amount of work as it would be pretty much remaking the game completely and it's not something I'm planning on currently.