Don't get me wrong, this manga isn't really "bad", but there's practically nothing to even review here. Just a mediocre little side story about Patema Inverted, too plain and honestly uninteresting to be notable or provide anything worth reading. I mean, there's seriously absolutely nothing worth noting about this story. I don't think something like that is worth reading. If you liked the world of the movie Patema Inverted, then the work might offer... something? But don't expect any great art, characters, or story here. I only recommend reading it if you are just the absolute biggest fan of Patema Inverted worldbuilding (even then itmight still be uninteresting as it only really manages to expand on the underground people's dwelling), but definitely not as a standalone or as someone who thinks the movie is none too special. I think you would almost definitely get more enjoyment and knowledge about the worldbuilding if you simply read a Wikipedia article with the information this manga has to offer; At least that would be direct and to the point instead of this nonsensically borderline ecchi thing we got. It doesn't even match the original tone of the movie, so that's also something to be aware of if you simply want more movie- this manga won't do it. It's not genuine, it's not philosophical, it has no tones of humanitarianism. It really just feels like a cheap semi-drama riddled with nonsensical slice-of-life bits, if you would even call it drama at all. It's more like the characters ran into an issue and get over it so fast that I'm not entirely sure if I'm supposed to take it seriously.

Well then, in conclusion (or if you simply don't want to hear my explanation), this manga might not be the thing for anyone, no matter if you enjoyed the movie or what. It's too different from the original to be enjoyable or knowledgeable, and its just a filler story with no content and lackluster qualities.