I really liked this game. The art style is amazing and it's very creative in the way it tells its story. So much about the presentation elevated it above the normal indie horror games I've played. I particularly liked the disjointed piano keys that signified each character's "voices". It's the perfect mix of being kind of jovial and silly but also creepy and unsettling.
I felt quite bad for you since Mark only played one ending (and not even ending 1) and then abandoned it without even seeing half of the game. Especially since you clearly intended someone to play all 3 endings. I was quite surprised by how much additional work and content went into the last one and there was clearly a lot of care put into the experience as a whole.
But because I genuinely like it so much and see a lot of potential in your game development I also have some (hopefully) constructive criticisms I've gathered while playing through it.
The first, is the reason I suspect Mark didn't play to see all the endings. I think having the player wait during every single playthrough when they're supposed to play it at least three times can get pretty tedious. Some way to skip these waiting sequences (the one with mom and the one with grandma) after the first playthrough would've greatly increased the experience and would also actually encourage someone to see all the endings.
The second point is going to sound a bit mean but I think it would be a good idea to have someone proofread your text. There were a lot of spelling and grammar mistakes that can make it difficult to read quickly and (in my opinion) just generally weigh down an otherwise great presentation.
Lastly, I've encountered a few bugs as well. There's obviously the softlock Mark found (which probably also contributed to him not finishing the game) but there is also a wall in grandma's room that you can walk through so you fall down the map and have to restart again. While being more minor than the other two, the text sometimes disappearing mid-sentence is another one of those problems that would really make the game feel more polished and improve the player experience if fixed.
But I really don't want these (relatively minor) criticisms to overshadow how much I enjoyed this. Many indie horror games have such problems but I truly believe that this is a lot more special than your average jumpscare fest.
Like I said, I loved the presentation of it and I hope you put all of this creative energy you clearly have into other amazing projects in the future. :)