Everything about the main characters comes full circle as we learn the full extent of their traumas and why they came to Mobius. Though interestingly Kotone's got cut short, I wonder if that'll be relevant in the fight with Wicked.
Going back to the therapy though, I did like how Kensuke was the one to instigate the discussion to regain trust (coupled with him waving around a conductor's baton). Made his joining the group feel a lot more relevant since his reasons for joining were completely different in the game also since they appear not to be adapting his relationship with Blumon (a salaryman who came to Mobius because of
Kensuke's songs) who doesn't even appear in the anime is sad as it developed his character so much. This line in particular...

Was quite impactful and drove home how problems may seem trivial to others but devastating when you have them. Also finally confirmation of several of the character's true ages - Shogo being 30 (though they left out how he's been in Mobius the longest at 10 years) and Kotaro being only 14 which is younger than he appears in Mobius.
Of course we gotta talk about that
bombshell at the end, Marie Mizuguchi did indeed turn out to be the final Ostinato Musician "Wicked". Why's all the good girls gotta be evil and/or crazy? T_T

Was anyone really fooled into thinking it was Ritsu? Although interestingly the PS4 remake actually has a new alternate story campaign where that happens and the MC betrays the heroes and becomes a Ostinato Musician instead under the name "Lucid".
Anyways, I do like Marie's outfit and how her tie (even in school uniform) looks like the signboard for "Danger", very clever foreshadowing that.
I loved how the gang were all so dumbfounded at Marie's sudden betrayal that they just stared at the grenade that rolled at their feet.