The Mari is Home event is particularly interesting. It can only appear if Sunny went outside on the first day. Meaning you either get here via the secret route in the Glade room, or you started Hikikomori on the second day by ignoring Kel.
The location is this version of Sunny's house. The most interesting change to me is the parents bedroom being down a long hallway. I feel like that's a metaphor for Sunny not being particularly close with his mom and dad. It marks one of the few, if only times, you'll see the grown up friends in Headspace, who say some interesting things.
>Kel: "We can't have a picnic without MARI!"
>Hero: "MARI hasn't been home in a long time... She just needs some room to adjust."
>Aubrey: "Hey, OMORI... I think your sister is ignoring us. Maybe you should go talk to her."
I kind of put this scenario in a similar, if darker spot that the Recycultist Dungeon is in. A sign of Headspace changing. Trying to incorporate the changes in what Sunny saw when he goes outside. Everyone's grown up and changed.
At the start of the game, you hear Mari knocking on the door. Saying she's finally back home, but she forgot her keys. Mari's dead. But Sunny's trying to repress that. To me, this feels like trying to excuse her not being home anymore. She's out somewhere, maybe at college. This Mari Is Home segment almost feels like a continuation of that train of thought. Mari Is Home now. But she's not seeing anyone at the moment. Omori should check up on her. If Sunny's mind wasn't precariously falling apart at the seams at this point, I wonder if Headspace could have completely changed and been more like the real world but with Mari alive again. This and the Recycultist dungeons being the signs of that change happening.
Also the ambience that plays here is...kind of nice, actually. I've been listening to it while putting together this image and writing this. I've liked listening to it. Even if I don't think I recorded the whole thing.
https://voca.ro/1mq88S1qGZDI