We've been hard at work trying to figure out why it's crashing on FireFox, unfortunately not with much luck yet. Web builds can be tricky! It hard to say if yours is the same issue or something else without more information. Were you on a windows PC when you tried?
Either way I'm sorry for the frustration! Maybe try again when we push the next update and let us know? It should be up tomorrow. Or try to play the downloadable build :D