When you realize Kuvira picked the Slave Route
Great update, especially since it was done in less than one and a half months.
I love how we get Kuvira content earlier than the ending, and how this gives us motivation to turn the tables on her later.
It's also nice that they don't slavishly follow the cartoon's story when there's opportunity for fitting additions like this prison segment.
It's astounding how much more care and planning they've put into the story structure compared with the Slave Route this book. Instead of you doing random shit as Tenzin while Korra fights the Equalists off-screen, you're actually involved in the conflict together with the girls you can fuck. Compare going to the Water Tribe vs. going to the swamp. One was a pointless diversion while the other was an important step in Korra's healing and your relationship with her.
And it's not a Slave Route vs. Love Route thing either. Book 2 and 3 had Slave Routes where you were involved in the story (the Fire Nation military coup and the Dai Lee hypnosis scheme) and got berated by strict teachers that you eventually got to turn the tables on in a satisfying way.
People say Book 1 needs to be remade, but the only problem with it is the limited scope. It's not bad, just short. Book 4 Slave Route, on the other hand, needs a re-write to reach the standard of the other routes - a re-write where the player breaks Korra, not Amon doing it off-screen.