I have another thing that sat on my mind for some time now.
It's about bugs.
For long i wondered how bugs are connected to the story, and while what i came up with might not be the 100%, i guess it's close.
We have a couple of bug nets in some scenes, even one is a talking being with a knife for a mouth and whatever for eyes and speaking during some (reset/happy?) events.
So far what i got from animes and japanese games, bug hunting seems to be a thing in japan for kids.
Though i take this with a grain of salt, because those two sources might be overstatements.
Like cultural depiction in fiction vs real life.
Whatever.
Some people think that bugs are associated with Sekai.
And i share that opinion in this case.
I could see how Akira as a kid was into bug hunting, hence we get the bug hunting nets in some scenes (mostly reset/happy?).
They could be metaphors for a time Akira was into bug hunting and when he went out into the woods, he was accompanied by Sekai.
That might have been the first time and place he was "assaulted" by her.
Making it "their" special place (the woods/forrest), "a place where they can be free", "where nobody would find them".
Tl;dr
Bugs and bug hunting nets are metaphors for the time and place Akira and Sekai's "history" started.