Tate no Kuni

What a weird manga.

The story is very confusing and there are a lot of plot twists and that's the interesting thing about it. I want to know more.

Characters in the start are not that interesting (probably because it starts right into action, but I like that so) but the more chapters you read you start liking them and wanting them to accomplish the things they need to.

The story has a lot of time travel and teleportation so be prepared to be "wait what" when it starts to happen.

There are some little plot holes (like a character had a solar panel even though in this world he shouldn't even want something like that) but they didn't bother me too much.

I didn't research anything about it so what I say next should be taken with a grain of salt.

It feels like a passion project, the art is bad (it gets a little better after) and the manga starts right into action but it already grabs you with questions about the world.

I feel some nostalgia reading it, because I feel like the author had the idea and went with it, instead of thinking too hard and ended giving up, it inspires me to actually finish my stories.

My only fear is that, even the author doesn't know what is happening and when the time comes to give explanations in the end of the story he ends up not doing it or give a stupid one, but for now I'm having a blast with it.

Tate No Kuni (The Vertical World) is one of the most unique manga I have read. It looks childish but the story is not something a child would easily understand.
I am still reading it so I will try my best to express my thoughts so far on it.

COMMENTS from Manga Plus (an Official reading website/app by Shueisha): at first readers were not impressed by the Art. One reader described it as 'reading a storyboard' with unfinished drawings (or you could say 'Name' as manga creators do). However, others were impressed by it being different from other manga art types and they liked it. Readers also liked the concept of the story which is good to know.

This manga gives off 'Made In Abyss' vibes and has philosophical theories surrounding it (my opinion as a Philosophy student). There was an Engineering student reader from the comments in Manga Plus and they found the manga's concept in the aspect of science also intriguing. It was not heavily focused on Science as 'Doctor Stone' is but I found lots of things in it that had to do with Philosophy.
If you are new to the subject Philosophy, the manga won't be a very good start. But if you are familiar to it, then this manga might intrigue you. It may not be as much as 'Neon Genesis Evangelion', another anime/manga that questions life purpose, the existence of deities, loneliness, duties and responsibilities, etc. If you are into novels too, 'The Little Prince' will be somewhat similar to Tate No Kuni's story but The Little Prince has a very impressive story.
If you are wondering what is Philosophy: it is from the word 'Philosophia' which means Love of Wisdom. This subject questions topics and tries to give answers(which mostly leads to debates/arguments and more questions).

STORY- in Manga Plus, the manga is read 'vertically' as the title says 'Vertical World', the option to read from side to side as in pages is not even given. This gives a special vibe to the one reading and I believe that is an amazing experience.
Similarly to the manga/anime 'Made In Abyss', the characters try to reach the bottom of their world in search of a precious/loved one. I like stories like this. They meet other characters who will be of help or have similar goals and continue the journey to the bottom. Their world is really hard to understand but you will get on bits by bits. Even the characters do not understand their world so they are looking for answers. If the characters do not know then you should not be heavily bothered but let's just hope the author isn't forgetting the main goal.
I rate the Story 7/10 for such an exciting story with philosophical topics like 'What is the world we live in?' 'What is our life purpose?' 'Were we created or how did we come into being?' 'Are there deities or people watching over us?' 'What is a duty?' and so much more to be debated and discussed. As for the Physics part of the story, I won't really understand. Maybe you might.

ART- it is okay for me. As I read more, the artwork becomes less of a problem to me. Maybe the manga will be great as a novel instead. They are simply drawn and not much. Some readers complained. Others did not mind at all. I don't mind either.

CHARACTERS- they aren't anyone with complex personalities. They are the 'easy to understand' type of people. Well, until the story progresses, then you get hit by the fallen maiden's character (the female MC they are looking for). That's where I got curious and not understanding anything about her or where she is from.
I believe the fallen maiden MC is the one who keeps the story interesting with the whole physics and philosophy side of the manga which is cool.

ENJOYMENT- yes, I enjoy reading the manga 7/10. I hope there is/ will be a paperback light novel of this manga so I can read it without the artwork. I feel it would be more engaging and nicer to read that way.

you can give it a try if you're interested in philosophy or science explanations or debates about time travel, space, etc. I do not think the science parts are genuine but hey it's interesting though- true or not

The Vertical World is when you take:
・ the deceptively whimsical art direction of Kaiba,
・ drawn by a worse artist than Mob Psycho 100's ONE,
・ set in a BLAME!-like world,
・ with the plot escalation of Homestuck.

There's a few more interesting similarities between the Vertical World and Homestuck:
Both comics integrated their unorthodox web format into their storytelling. And both comics deal in similar high science fiction concepts, namely time, space, infinity, relativity, information, alternate dimensions, nested realities and circular causality.
In that regard, there's only few mangas or animes that tackle these topics as deeply as the Vertical World does. Because in order to touch on all of these subjects, you'd need to create an alien and arbitrary universe, and then focus on the exploration of that universe. You can really tell that the author is very interested in astrophysics - not just because most (or all?) characters are named after famous scientists or other scientific phenomena. Some plot twists/conveniences might seem a little random at first, but I suspect the author does have a clear goal in mind, and he doesn't forget places and events that might contradict some of his new ideas either. Lots of times I thought I finally had a good grasp on how the titular vertical world works and where the story would go, but then a new revelation shattered my understanding and revealed a much deeper truth.

Without giving too much away, all I can say is that it's EXTREMELY interesting and well worth a read when you're at least somewhat into science fiction. You just need to get over how bad the art is.
Thankfully, the manga is very accessible as it's getting the simul-pub treatment on the official Shonen Jump website.