Ishiguro Aya took the stage for a Tanpopo Medley:
There was a near complete first generation reunion:
Goto Maki made an unannounced appearance to participate in a Pucchi Moni medley:
Tsuji Nozomi also showed up. Her main subgroup didn't get a medley:
Morning Musume performed their upcoming single 'Renai Hunter':
And then everyone (sans Ishiguro) performed together. There was a serious clash of outfits and it was probably glorious:
Sources: 1, 2, 3
Too many amazing people on one stage, tbh. The DVD is going to be awesome.