I don't normally watch compilation movies of TV series, but I did here.
(a) the original show was excellent
(b) there are three Made in Abyss movies. The first two are compilations, but the third is new material. As a warm-up, I thus decided to watch the compilation films first.
For what it's worth, it's a story about small, cute children. They're about twelve. They're adorable when they're being childlike together. (Riko's glasses are also super-cute.) Riko lost her mother ten years ago, but she knows where she is. Mum's in the Abyss. One day, Riko and her robot friend Reg (Leg?) go into the Abyss to find her!
If you think that sounds a bit Ghibli, think again. The Abyss is a pit of abominations, death, vomiting, insanity and surreal man-eating monsters. Going past a certain point for inexperienced Cave Raiders is treated officially as suicide. Even returning to the surface can be fatal, thanks to the Curse of the Abyss. It's like the bends for divers, but worse. If you didn't go too far, you'll have nausea and dizziness. Deep divers are in for bleeding from every orifice, madness, mutation and death. This is not a kiddie show, unless you were hoping to shock and traumatise them. (It can be pretty tough fare for adults too.)
This is only the first film, though. The nastiest is yet to come. Anyway, let's do the maths.
THIS MOVIE: 119 minutes, of which the first four minutes are original. We see two flashbacks, one 1900 years ago and the other 12 years ago, when Riko's mother was pregnant with her.
CORRESPONDING TV EPISODES: #1-8, each of which is 24 minutes long, or 21 minutes if you exclude opening and closing credits. That's 168 story minutes, so this compilation film has included 71% of the available material. That's a lot, actually. I'd still recommend watching the TV series over this, but the film flows and feels complete.
Anyway, it's good. The children are lovely, especially our heroes Riko and Reg. (That's "Reg" with a hard "G", rather than being short for Reginald. "Leg" would have been a less misleading official transliteration, but never mind.) Riko loves all things Abyssal and can be funny, e.g. when announcing the results of her investigation into Reg. As for the robot boy himself, his powers are super-cool but his meek personality makes Riko the unchallenged leader.
It's also a joy to watch. The worldbuilding and its on-screen realisation is superb, not just with the Abyss itself and its monstrosities but with the surface-dwellers' slightly steampunk technology and even their architectural choices. I love that vertical classroom. Even Riko's bedroom is fascinating. "Do you guys work as torturers?" These are the kind of visuals you'd love to see on a big screen.
It's a memorable start to a story that's only going to get stronger. It's hard not to respond to its combination of adorable children and shocking things happening to them. It's a bit on the long side, but long is good. No one wants to see a butchered, rushed compilation film. I'll report back on movie #2.