I couldn't register, the game would just never finish registration. I tried to sign up with the (fake) email 2hu@4u.com and the username 2hu4u. The same thing happens if I tried to log in.
Viewing post in Strategic Supremacy jam comments
Seems like firebase has great timing with going down dammit... :V https://firebase.google.com/support/
Seems like it works again now...