This is actually a better question for @lynnedrum or Christa, since they did all the hard work! Personally, when I look at my favourite RPGs, I feel like my absolute favourites are ones that have music with a unique character to it rather than ones that follow genre conventions, so it was very important to me that the team felt free to put their own voice and interests into them rather than listening to my own dictates. My decisions were mostly very broad strokes like "battle tracks should have dramatic lyrics" and how many songs we could budget for (it felt very important that the final boss have all new music, and it had to match the dramatic arc of its many phases), but past that, I was very happy to let them go where their vision took them. They could probably tell you more about that process, though, I'm not a musician! All I can really tell you is that it was a collaboration with a lot of back-and-forth between the two.
I did basically no work on the lyrics either, that was all Jami. My only contributions were a couple of phrases—the recurring "the spirit of the times" motif throughout the game that also shows up in the main battle track felt important to me to emphasize, and the final Orphan fight having a reference to Emily's "I will not falter" sign—but literally everything else was all her. In general I think she knocked it out of the park with the lyrics everywhere, but I was especially delighted by the boss battle music being a break-up song, which I think really helped cement a unique character to what the game's boss fights were about that I had never even considered. As for the Orphan fight music—my absolute favourite in the game, for the record, I was completely floored when I heard even the initial rough mixes—I actually loved Jami's lyrics for it so much I went into the final Jo scene and sprinkled some of the mannerisms and phrases from it, like the "hush, little heart," into her dialogue to make it feel more strongly tied together. That part of the character's voice was all Jami, though, it's a reverse callback!
Also, I know I've mostly focused on Jami's contribution here because as a writer I ended up interacting with her lyrics the most, but I can say for sure that a number of scenes only worked as well as they did because of Christa's background music—composing something to match the tone of the pre-boss banter was a tough ask but she knocked it out of the park with the incredibly sick track for that. Also, the GasLINE presentation would not have been nearly as funny as it was if she didn't match the tone of it perfectly with that track.
I guess I'm mostly just bragging about how great the team was, but imo they really do deserve the praise. GITCL has some of my personal favourite RPG music, and I feel very deeply lucky to have gotten to work with Christa and Jami on it!
