After being excreted from Monstro's nose, the gang flies to the next world. Atlantica is being predictably attacked by the Heartless and it shouldn't be too hard to figure out who is behind it all.
Finding Atlantica: 1:40 - 2:20
Intro to Atlantica: 2:20 - 3:49
Meeting King Triton: 23:05 - 25:50
Spies!: 30:15 - 30:45
Not So Fast!: 45:05 - 48:15
Ha Ha HA Ha!: 52:04 - 53:30
Boss Battle: 1:00:05 - 1:03:35 [Ursula / Flotsam & Jetsam]
Boss Battle: 1:07:30 - 1:15:25 [Ursula]
The second battle is the first "real" battle in the game. She has a ton of health and button mashing won't cut it here. Still, there may be some points where she can be taken advantage of. It is possible to stay behind her at all times. The lightning remains an issue though.
Sealing the Keyhole: 1:17:30 - 1:18:55