"Title Theme" super nice requiem feeling, caried through with the piano and strings at an appropriate intensity/gentleness i feel that fits the claustrophobic feeling you mentioned effectively. It opens beautifully and love how it's structured to wind down similarly in a gentle, quiet way.
"Flower ending" woww!! definite miyazaki vibes, while walking through emotions in a way that stands on its own, and excellent performance (coming from me who doesn't perform :P). Great development of the idea, for a beautiful piano string work.