If just a couple of these stories showed up in a more varied collection of Ito stories, they would have been more interesting. I mean, there are some interesting things going on in this collection, as is. While the "bad" little sister character is sort of just... girl-Soichi++ with little to do besides to explain the plot while acting creepy, the older brother is a pleasant (well, as pleasant as a devil worshiper who melts people can be) twist. He is a cute, polite teenage male who has been bound to the devil, and his apologies melt folks brains (and the rest of them).
According to the afterword (a short comic, itself), he is a reference to Sincere Apology(tm) culture, where some such-and-such does something bad and then makes a big public apology (Sincere Apologies do not need to be sincere, though they might be). I suppose this makes this something like social satire, but also not really. Sincere Apology culture has gotten louder, if anything, since Ito wrote these, and watching legions of Youtube commenters and Redditors implore you to remember the good that their favorite publicly maligned Let's Play-er did (and by "good", it sometimes comes down to being funny while playing Minecraft, basically) can very nearly equal a real-world version of these stories.* Perhaps that's what Ito was talking about, precursors to these. I don't know. Maybe he just liked the idea of a handsome young man being too polite, upholding society ideals a little too much, and it melting people into goo (I mean, his little sister's favorite snack is melted brains, so you could even argue that he is just being a good provider, like some weird perverse version of Grave of the Fireflies).
The chief drawback of this collection is that it is a collection, albeit short, of this one storyline, over and over. Putting much the same plot on loop dampens the punch a bit (oh, these heady days where a room full of human proto-flesh rotting away fails to sustain its own surreal horror after the third samey page). Much like the Tomie collection, there are variations on the theme, but where Tomie took years to grow and develop, these feel much more "all at once" (though I assume there is some gap between them). After you get through "Dissolving Apartment" (the third of five "Dissolving" stories) it goes through the basic Ito motions that he has done before. By repeating the idea, it makes the whole thing seem a bit simple without much room to grow (the fairly different second tale, "Dissolving Beauty," being the respite).
It is gross and grody and weird and very Ito, it just doesn't feel like it hits its full potential at any point.
It includes two fairly short and very different bonus shorts. The first is just strange and inexplicable, about a missing person and a meteorite. The second involves missing kids in a forest and the weirdness that happens when they are found. Neither go into any explanation, into anything like sense, and that makes them kind of neat, despite their slight length. Why two stories about missing folks and the "weird" of finding them were included in this collection, I have no idea.
* A subreddit I frequent, as much as any, recently came to the defense of a particular streamer with such arguments as, "It's not like he knew she was underage when he did it." There were a lot of these kinds of apologetics. Brain melting, indeed.