This episode combines story elements of multiple episodes from the original series, much like episode 3. IMO last episode handled that better.
::: spoiler Click for Spoilers There is a huge derivation from the original series in this one: Aang very quickly recognizes Bumi. Originally I really disliked this change, because it changes their dynamic as compared to the cartoon. But tbh they made it work. It's a bit of a "What if" scenario, and Bumi still stays true to his playful, game-y and testing nature.
I disliked the prison dialogue between Aang and Iroh, that was another typical Netflix exposition dump. Badly written.
I liked: the adaptation of the Secret Tunnel storyline (originally in season 2, interestingly) including the musicians and the badgermoles. Swapping Aang for Sokka is interesting. The adaptation of the Winter Soltice storyline of Iroh being imprisoned and his conversation with the earth captain, including the Lu Ten flashbacks, was also great. And the last few tasks set by Bumi also were really faithful to the original. ___