Houseki no Kuni is the dullest anime I’ve seen in a long time, which is ironic considering the gemstone theme. This review will go over why I thought so, and I hope you are able to understand my point of view.
Before that, though, I want to take a little bit of time to praise the visuals.
As you likely know by now, Houseki no Kuni is a fully CG anime. It also happens to be far and above the best-looking one, and uses the medium to its advantage rather than just as a cost-saving measure. The most obvious example of this is the characters’ hair, which has a captivating translucency that seems perfect for CG. And during the action sequences, the camera has these wild panning, sweeping, rotating motions to capture what’s going on from every angle. They never go too far as to be sickeningly fast, and add a lot of eye candy that would have been prohibitively expensive and time-consuming with traditional animation. There are a lot of great shots of the environment as well. Everything is lush with greenery and the “school” they live in has an imposing, hallowed sort of feel with its massive stone architecture. The only flaw in this sense is that since the events take place within such a small radius you end up seeing a lot of the same areas over and over. Nevertheless, in general the shot composition is quite good. A few shots in particular stick in my mind, like the scene in episode 7 when the gems go to sleep (incidentally, probably my favorite episode). And during calmer scenes the camera frequently is placed way behind any of the characters to show how small they are in comparison to the empty world they’re in. Overall it’s just quite well-done. Every other CG anime should take after this one.
Unfortunately, now we have to get to the aspects I didn’t like.
Visuals
Wait, didn’t I like the visuals? Yeah, but there are some definite improvements that could be made. The first is quite obviously the framerate. I must give credit to Houseki no Kuni for breaking new ground in the CG space and being the first CG anime to render everything at a barely-watchable framerate. This is a quantum leap from previous CG works which typically ran at about a silky smooth 3 FPS. But even if Houseki no Kuni has made strides in this department, a barely-watchable framerate is still barely acceptable, or perhaps not acceptable at all. I get it, Japan, buying rendering time is expensive, but you need to hit a full, actual 24 FPS. Anything less is too stuttery. If you can’t afford it, then delay the project five years until costs come down. I’d gush over 60 or 120 FPS but I know that is never going to happen so I will settle for 24.
Secondly, it's not a big problem while watching the show, but it's clear this is a product of a CG anime industry in its infancy. I mentioned the shot composition is often pretty great, but just as often it's on a bland shot of a field or two characters talking. As CG anime keeps getting better I'm sure directors will find more and more interesting things to do with the camera during downtime.
Finally, the character design, or rather lack thereof. Their heads and hair are different but that’s it - every character looks exactly the same from the neck down. A gangly CLAMP-style body, but with considerable hips, each in the same drab black school uniform.
"Wow! What Amazing® and Unique© character design!"
Actually, speaking of considerable hips, that reminds me.
“Gender neutral” characters
“One of these things is not like the others, one of these things doesn’t belong…”
I don’t really care a whole lot one way or another, but when I heard talk about there only being gender-neutral characters I was a somewhat intrigued. So I was a little disappointed when I watched the show for myself and saw that, for all intents and purposes, every character was just a girl except for Kongou. They may only use male/neutral pronouns to refer to themselves and others, but that doesn’t really affect anything at all. This isn’t really a complaint per se, but the “gender neutrality” of the characters just seems like a gimmick to stimulate discussion and interest in the series rather than being of any consequence.
Plot
Nothing happens. This is barely an exaggeration. For the first half of the show it’s Phos doing monster-of-the-week crap with a new buddy. Except it’s not even monster of the week since it’s basically just the Lunarians every time. Walk around, get careless, get attacked by Lunarians suddenly, someone gem breaks, everything is okay in the end. The developments are so inconsequential that if someone explained the plot of the first six episodes to you in three minutes you could go on to episode 7 without having really missed anything. The second half does have slightly more variety. In particular the winter scenes were a nice change of pace. Nevertheless just about all that happened was “this isn’t even my final form” Phos. There are no subtleties here, for any given episode you wouldn't miss out on much of anything by just reading the Wikipedia summary instead.
Cinnabar
I only mention Cinnabar separately from the rest because they are listed as a “main” character in the Anilist database. What a joke. They show up one minute per episode to mope then go back to their cave. Their inclusion is entirely pointless and only serves to act as some sort of anchoring point to pretend there is an arc between episodes 1 and 12. I guess this is enough of a segue to talk about the rest of the characters.
Characters
Every character but Phos is completely one-note and forgettable. Actually, I take that back, over half of them are zero-note. There simply are not any personalities; it’s amazing how bland the characters are. I’m reminded of the classic Phantom Menace review that challenges people to describe various characters without describing their appearance or role. I wonder how well people would fare with Houseki’s cast. We could add that you can't mention their hardness level either.
Perhaps those two are a little unfair. Despite popping up fairly often throughout the series they aren’t very important characters after all. Although one wonders why you would bother having thirty introduced characters in the first place if only two or three are of any importance.
You see my point. If you thought as hard as you could, you might be able to come up with more than one adjective for Diamond or Antarcticite, but that’s about it. No one but Phos is of any interest.
Phos
I made a mistake in the last section by implying Phos might be an interesting character.
Minor spoilers:
Spoiler, click to view
About the extent of their development is getting the ability to talk to fish and super-speed legs. Then later when the author decided super-speed legs weren’t very interesting, said powers were retconned away with Phos also getting golden Mr. Fantastic arms and a haircut. Not to mention that each of these powers were acquired in the same stupid way. Fishspeak, Phos is left unsupervised and she is eaten by the fish thing. Super speed legs, Phos is left unsupervised, gets easily tricked by by said fish and is knocked around by Lunarians. Golden arms, Phos is left unsupervised and falls into an icy pond. Why are you still leaving this incompetent gem alone!? Maybe this was Kongou’s plan all along, leave her alone so her arms and legs will get ripped off and then level up conveniently. They should just do this with all of the gems. Additionally, I have to question what this means symbolically for character growth. If you’re weak, you’re useless, but if you are also a huge idiot and put yourself in danger repeatedly then you might get sweet cyborg limbs? I have a hard time thinking that was the intent here, so the only interpretation left is that these were just cheap tricks to keep the main character relevant to the meager plot somehow.Halfway through the show Phos’ character changes drastically but I have a hard time accepting this as a “character arc.” It’s more like they’re one character the first half and another character in the second. This change comes off as forced as if the author couldn't figure out how else to progress the story.
The ending
I wasn’t invested in the show by the end anyway so I didn’t care that much, but prospective viewers should be aware that this anime has a non-ending. I can’t fault Houseki for that too much though as it’s just the realities that come with adapting an ongoing manga.
Conclusion
I suppose that’s about all I wanted to say. Truly, without meaning to offend, I am not sure what people liked about this show. The OP was nice, the music was very good, the visuals were flawed but intriguing. Yet that’s about it. I can’t help but feel this got the attention it did primarily because it was CG, rather than that being a detriment to its popularity. I’ll end it off with a quote from mathemagican’s review on MAL which sums up my feelings pretty well:
“A bland cast of characters fights a boring monster of the week that goes nowhere. How dull.”