Just marathoned the whole thing, really didn't like the direction this story took around chapter 9 or 10, when the story dwelves into infinite universes of infinite Gakus trying to save Yukari, and also the yandere thing later on.
It reminds how pointless all her strive and just about everything else is.
It doesn't matter if one of her possibilities saves her because in an infinite number of universes she never needed existed to begin with. In an infinite number of universes they are married, living happy, in an infinite number of universes they hate each other to death, in an infinite number of universes they really never existed because they were never born, in an infinite number of universes planet Earth doesn't exist or just doesn't support life like Venus and so on...
Her strive is pointless because of this not to mention that the whole story became a huge convoluted mess!
I liked the story "infinitely" better when the author was keeping light and humble with the quantum mechanics, I liked chapter 07 and 08 with the Shrodinger's cat and other things, but the way it dwelved itself so deeply into exploring other aspects of quantum mechanics just turned it all into a mess, which is a shame, this was my favorite manga before it turned into this trainwreck. But in any case, in an infinite number of universes I'm really enjoying the turn of events the manga took.
The author's non-sense reached its apex on the chapter about the anthropic principle and how the universe could have been made to suit humans, when that not only misinterprets the actual notion of the observators but also introduces too much for the story to be able to handle it, convoluting it even more.
The last two chapters were beautiful, though.
One thing I enjoyed was researching terms and ideas that the manga introduced, and ideas related to them, like Dualism, Monism, Physicalism, Panpsychism, etc. As a tour into philosophy and physics this was certainly rich.
Also, I believe the tag should be only sci-fi
without supernatural
as all of it is based on quantum mechanics and such in a sci-fi nature, even if taken to an extreme, unless I'm mistaking what supernatural actually means.