The childhood friend is winning but at what cost

bruh the cgi is anoying

wtf just happened?

How tf is she alive

from just watching this episode, and nothing else, i can theorize that :
this is a time travel anime, where the first 20 or so minutes are the timeline where "Kaori" died.
that part with the outro song running, would then be a replay of that timeline, but something changed, there was a sound from upstairs and there is now a girl over there. also notice the dialouge at the outro, its the same dialouge from earlier