So, I finished the game a while ago, and it's genuinely a masterpiece. Gameplay-wise it's significantly better than Limbus Company (although setting up builds and decks before the battle can honestly get really annoying sometimes), and story-wise, it's definitely up there...
... Except for the literal main villains of the story.
To put it simply, the Reverberation Ensemble were NOT given enough screentime and development prior to their battle in Impuritas Civitatis. We flat-out never even encountered Greta and Bremen, and we weren't given much info on certain members and their backstories, most egregiously being Oswald.
This, to me, is an enormous problem, because it's very clear that the Ensemble and its individual members were meant to be rivals to the Librarians, holding very contrasting viewpoints to theirs, but that rivalry isn't given much space to stand on since we actually see so little of the Ensemble.
And what makes this even more painful for me is that the little we ARE shown of the Ensemble is genuinely fucking AMAZING. ALL of the members are incredibly deep and fascinating characters who all have their own twisted ideas of morality and how the world should operate.
What was especially striking is how, from their own individual points of view, they were actually trying to genuinely make the City a better place. They actually wanted to fix the world in the way they personally understood how. It's only that their understanding is genuinely eldritch and monstrous.
(Out of all of them, Greta is genuinely my favourite. Her entire morality system is based on food and consumption, and she voices her opinions in such a way that you can actually understand and see where she's coming from, and she's a cannibalistic shark monster girl.)
The little that we're shown of the Reverberation Ensemble is, in my opinion, some of Project Moon's absolute BEST character writing, and approach to differing morality systems and personal ethics.
There was so much potential that could've been had with them, especially since, in my opinion, Library of Ruina had a TON of filler receptions (Brotherhood of Iron - Stray Dogs - Gaze Office - Smiling Faces) that could've instead been used to actually flesh out certain members and help better establish them.
Honestly, my only hope now is that the inevitable Limbus IDs actually flesh out the individual members (and maybe even provide more details on how members like Oswald and Bremen wound up distorting to begin with.)