The world in this manga was without doubt the main selling point, or rather the only selling point. Which is perfectly fine for me, as I can easily enjoy a piece of work immensely as long as it has at least one very strong and creative point.

Unfortunately I can't say the world was perfect, or even brilliant, at most I can say it was decent. I found the world presented in the early chapters highly bizarre and full of wonder. Yet as the manga progressed I couldn't help but lose interest in it.

The main cause of my disinterest was the fact that the author didn't allow for reader interpretation, he diluted the wonder by leaving little to the imagination; it's a problem in the same vain of author's not trusting in reader intelligence, they believe that the reader's won't be able to read between the lines, so they jam in exposition dump after exposition dump to explain everything and ultimately leave no subtlety in their work.

There were multiple subtle world-building moments in the manga that were completely negated by an unneeded explanation soon after.

Basically the world was explained, the meaning and theme were explained, and even the very last questionable point in the manga was explained, which I find is a pretty bog standard path for a manga that had such imaginative potential to take.

Interestingly enough the characters were actually harmed by the world they inhabited, which I find is a bit of a deeper meaning that the author didn't intend for. You see, all the characters, with the exception of two, were merely mouth-pieces for the world, they existed to explain the world, which even though sounds philosophical is ultimately shallow. If the author had replaced these exposition-characters with fully realized and interesting characters it would have improved not just the characters themselves but the world as well, allowing for it to appear even stranger and mysterious.

The only two characters actually worth naming are Pipi and Kai. Even though both of them are fairly shallow in their own right, Pipi more so than Kai.

Pipi is actually a pretty terrible character by all standards, yet she can at least be called a character, unlike the world-expositors. The problem with Pipi was that her entire character was defined by her love of Kai. She had no goals, motivations, relationships and traits outside of the box known as Kai. Funnily enough the one shown interest she had outside of Kai, her garden, was even revealed to be some esoteric profession and dedication of love towards Kai in the final chapter, which fully rendered her character as 100% Kai defined.

Kai himself was also fully defined and obsessed with another character, though in his case it worked much better, simply because it worked in tandem with the theme of the manga and raised some interesting personal questions. Though he had basically no personality.

There was one plot twist right at the end of the manga, which I felt was pretty ridiculous. The plot twist itself didn't surprise me as I had thought something along those lines was going on in the first chapter, where the first foreshadow for this twist appeared. The bit that I found ridiculous was the other characters complete lack of reaction(with a few exceptions) throughout the manga, at what should've of been a pretty telling situation. Really I feel the twist shouldn't have been explained at all, and the author should have simply left all the foreshadowing as an interesting little mystery to those paying attention, it would have at least kept my suspension of disbelief in tacked.

Overall this manga felt weak, it unequivocally answered every question its theme brought up, which I don't doubt some enjoy, but which I find a pretty boring form of world-building, a form which makes the world feel tiny and unimaginative. The moral questions are also given answers, and I shouldn't have to explain why that's dull. In spite of all the problems I had with it, the manga was much more interesting and creative than what is usually served in this medium so I would definitely recommend it.