Missed 15 min of finale; someone please Help! [Spoilers]

I recorded the season finale this morning and because of the abnormal run time it awkwardly recorded the episode in 2 episodes: a 45min recording which ended at 11:45 and the last 12min of the episode in a different recording that started at 11:59. So the way it played out for me was was: Korra lost her bending, Naga metal bends like a boss, recording stops, Mako and Korra are looking out over the water as, I assume, they've blasted their way out of the arena, and resume episode as usual. WTF happened?! I don't care too much about watching what happened b/c, well, Aang showed up and really, that's all that matters. However, I would like to know things like, what was w/ Amon's new face and how did Korra discover the new things Amon unlocked, and anything else that might have been important that I missed. First time posting on Reddit, so, sorry if I did anything wrong :/