What a lovely experience! (Here's your obligatory spoiler warning).
Ok, where to start... I would like to give you a congratulations on nailing the story and presentation of the game. Most of the time, these types of games feel cheesy or Game Jam-like. However this time around, it felt more "real?". I'm not sure if it's the characterization or if the light-hearted absurdity but the game made me empathize with the characters in a way that I did not expect. It's not groundbreaking, just sweet.
It's always so enjoyable to see people push simple premises to their limits. It goes to show that sometimes all you need is a good creative direction. I can easily see ways it could be expanded upon. I'm sure many people would love to see even more of your signature creativity.
Button was quite relatable to me for better and worse. I believe her people pleaser personality meshed well with her own occasional bouts of self autonomy, the likes of which isn't commonly different than my own. She knows her boundaries and yet still tries to keep close to "Finn" whenever possible, making the most out of her life even if others aren't willing to do it for her. Bad End 8 however, also displays how such attributes could be pushed to the extreme. The way she selectively ignores the world around her in order to feed her own negative thoughts unfortunately feels oddly familiar. I'm not nearly going to dissect "Finn" that hard. Personally I feel like he speaks for himself.
Anyways, congratulations on telling a strangely demented yet endearing story. I still wonder however how to actually get the tenth ending though...