I should have a theme song for Maya, the main character from Depths, since she's a musician herself (piano). I feel like Page d'Album by Debussy might be a good fit.
Before the events of the story, she's very much absorbed in the loneliness that comes with living alone at the bottom of the ocean & finds solace in the memories of her dead parents. Page d'Album has that floaty feel that moves between nostalgia and melancholy. But then again, I feel like I'd have to choose a completely different song for her by the end of the story.