tl;dr: A manga that’s mostly a gag manga with a good amount of serious moments, but that don’t really carry forward into an actual plot. 

This is mostly a gag manga in that it’s focused pretty much entirely on comedy, without any sort of overarching plot. It’s generally a bunch of small episodes having to do with random problems the monsters of Kodaira face, with the occasional flashback providing background on the monsters. Now despite there being a gag manga, there’s a surprising amount of serious aspects. The thing though, is that because there isn’t really any overarching plot, while these are interesting enough on their own, they never really amount to something more substantial and hence don't have any sort of impact, thus they don’t feel like they have much value. For example, it goes through the background of pretty much everyone, but with most it's just a flashback that doesn’t affect anything at all, and for the others where it does have an impact on the current point in the story, it’s usually just for that chapter and never brought up again. There isn’t any depth to the story or characters. They’re completely flat and don’t go anywhere beyond where they started at the beginning of the manga. They’re not bad characters, but without more to them they feel kind of boring. Regarding the relationship between the main characters, that’s the closest thing to an overarching plot thread that develops, but it’s not really built that well. Its something that’s being pushed from the beginning to the end, but it doesn’t really develop, it just stays in the same state for the vast majority of the manga until the end where it suddenly works out. That’s better than it not working out I suppose, but it isn’t all that great either. As for the comedy itself, it was decent enough, not really funny, but not bad, although a bit repetitive. The art was pretty weak even though the setting and subject matter were interesting visually.