The first two chapters where they have Hajime visiting Reiko's apartment the most considerable difference in Reiko's personality. Back then she had a much more laid-back cool older girl personality. While now, she has a more girly personality. Though despite that, her apartment looks very much the same. We know humans are creatures of habit, so could it be a scenario where her habits haven't changed. Though the personality difference with the same habits sounds contradictory?
The big reveal that Gwen is around and what he and Hajime say to Reiko is a lot to take in. Gwen mentions that the old Reiko isn't of this world. Even more heartbreaking is when Hajime says that he hates Reiko. The fact that Hajime mentions that the only person who doesn't know that Reiko isn't the same as the old Reiko is the current Reiko. I am mean the personality difference really show this off. Still, the big question is: How did she become like this? Though when he says that her love for him is an illusion, and it comes from the old Reiko is very heartbreaking.
Though one thing that is clear is that Hajime still cares for Reiko. After all, he stayed by her side. Even more so, he still has her spare key. After all, just seeing that makes it clear his feelings aren't hate. Or you could say perhaps he hates the old Reiko? Though Reiko refuses Hajime's proposal of learning about the old Reiko is surprising. But it gives her a lesson as dealing of learning this other Reiko it is more important for her to move forward as her own self. Though with her feelings with Hajime and not knowing what happened makes it hard.
It is quite curious to learn what Miyuki is planning since it is clear that he put out that article that he was adopted. Or could it mean like Reiko, he has an old self and that is why she caught his interest? Though once again he mentions the power of nostalgia is something that can't simply be removed. Which clearly is a major theme in this series as it is both a love and wanting to keep something close to you. It is something you always want to come back to. Though Miyuki's desire for the absolute. Only guess can be that he wishes for a world where everything is as close to perfection as possible?