Thank you for your kind comment! I also thought about expanding The Starry Sea a bit more, it definitely has the material and space to be developed further. I did give a try but then it started to sound like some kind of music for a story climax, so I scaled it back a bit and instead went with a more low-key recapitulation to end off the piece.
I'm glad you liked the vocaloid! I always planned to finish the OST with a song, since it would make the ending feel more personal and resolve the narrative better. But yeah, making my gen 4 vocaloid sound less robotic and more natural took a lot of tinkering! And even after all of that, it still butchers a lot of the Japanese... Hopefully not too many people pick up on that...