Oh my God.. I heard all of "21st Century Breakdown" the song, and it is amazing....and its only the demo. It reminds me almost of the song "Homecoming" off American Idiot. Wow..... I also heard a 40 second clip of "Know Your Enemy".... Which is even better than the title track to be honest.... I'm very much looking forward to the album, and all of Know your enemy in a couple of weeks....
Know Your Enemy (40 second clip):
21st Century Breakdown (song- over 7 min long!)
There is also this song, but I don't know if it actually is Green Day as there are no vocals, just instrumental.
Last Night On Earth