Sounds weird, right?
Made in Abyss is prime example of poorly executed great idea. This show had everything to become a modern classic, but wasted it on bland characters, poorly paced dull story and blatant fetishism.
Worldbuilding
Made in Abyss sets up one the most interesting fictional world to explore, but barely does anything with said world. Since episode 1 you'll be showered by paragraphs of exposition and ramblings about great adventures, but the Abyss itself is very shallow. It does look pretty, all thanks to amazing background art, but it's empty as desert. 3-4 species of monsters per layer, no foreign delvers, no artifacts to collect, nothing of what you can expect by looking at its map and listening narrator's voice.
I still think Made in Abyss is worthy to watch for the world alone if you are tired from generic fantasy/isekai setting, but actual Abyss is one big missed opportunity in terms of worldbuilding. Monster designs, landscapes, idea of the curse field are great, yet plain and tiresome story doesn't allow them to shine.
Story
It's linear and aimless. The most interesting part of the story are flashbacks and it speaks a lot. Somewhere in the middle of Ozen's arc I questioned myself: "why do we even follow Reg and Riko, when Lyza's past seems 10x times more interesting than her daughter's speedrun?"
The shock value and horror may have worked if there would really be consequences. Despite building up the dangers of the Abyss nothing of lasting consequence actually happens. For every time main characters are getting into troubles there is always Deus Ex Machina to save them.
Characters
I don't have prejudice against children as main characters, I think that immature protagonists can be incredible opportunity for a writers to show how the horrors of the Abyss can warp unprepared young minds. Alas, for an author of Made in Abyss it was an opportunity to show how 12yo girl pees herself almost every episode.
I was expecting the characters to be more developed than what is the standard fare for shounens, but Riko and Reg totally fit into what every main character of shounen series are, despite Made in Abyss being seinen. The worst part is that they don't grow because of their hardships, they just stay as naive as in the beginning so the viewer would feel bad for watching suffering of cute, innocent kids.
Side characters are slightly better, but they don't have enough screentime or proper arcs e.g. Ozen, who was intriguing, but actually exists for exposition only.
Nanachi's part amused me at some point by how writers tried to brush away the fact that cute bunny tortured almost as many people as its creator. I was seriously disappointed that potentially interesting morally grey character turned into a token furry loli at the end.
Drama
I've heard million times how this series is sad and depressing. It's not, if you wouldn't allow to fool yourself by simple tricks. Made in Abyss essentially skips all needed development of emotional connection between viewer and characters and makes you feel bad for them because they are small children. It uses every possible tearjerking trope in a span of one episode from cancer like desease to loss of pet and sweet tragic girl, who fell for some loser. For me, it's jumped the shark.
Art&Music
Background art is incredible, music carried half of the overall enjoyment. I liked monster designs and White Whistles. Architecture of Orth was also great.
tl;dr: Made in Abyss has an interesting setting and the production values are excellent. But it seriously fails with the main characters and with the laughably forced melodrama.
