This is so emotional right from the beginning, the music kinda revealed where it was going but then I started to think about my own previous pets and just cried when throwing the ball one last time. What a soul purifying and destroying experience. You really nailed the storytelling part (and also the other parts), what a genius masterpiece. 5/5 game in every category but I'll never want to play it again.
ALSO the way you tell the story via simple gameplay works really well, it reminds me of Edith Finch and some of the minigames there, especially the baby bath and swing ones. Don't know if you've played it but had to mention.