Wow! What a beautiful and incredible experience! I haven't cried in many a year, but this very nearly got me. To be able to write such a lovely, heart-warming story with the perfect amount of comedy sprinkled throughout whilst also retaining the overall thematic outline of the jam - you've executed that with aplomb. I was smiling almost all throughout (until the latter portions)!
The character building and bonding were done excellently, and felt natural and genuine, even in such a relatively short time. I also think you hit the sweet spot with pacing and overall length.
Solid sprite work! Echoing other comments, Yuna's expressions were phenomenal and hit the funny bone just right for me. Absolute chef's kiss.
Of course, it's very impressive that you've managed to put all this together by yourself, and you should really be proud of this project, but I think you would benefit from having 100% original assets throughout. I'm sure you have your reasons for working solo on this, but I believe getting other people involved to create original background art, music, SFX and potentially even voice acting would take this project to the next level. Something to think about, at least. I'd genuinely pay for a story of this quality if the overall experience was improved and embellished. Side note, the music you did choose to implement worked pretty perfectly and I'd imagine it would be hard to let go at this point anyway.
I'll be coming back to see ending B and C once the jam ends. Congrats on such a great piece of work, looking forward to hearing your future plans. All the best!