Hah! Yeah, we left the debug console open so you can play with it. It's a graphical debugger that shows the data updates for the game in realtime. Have fun: http://mmoa0.firebase.com/mmoaleaderboard0
You don't need the debug console, though: the database seems to simply be a shared scratch space, so anyone can just manipulate anyone else's state using the JavaScript API.
Oh no. I predict that within the hour every player will have a rage face as their player picture.