Complex Society is a harem VN about the incestuous love a boy has for his mother and sister and the secret Illuminati-like society dedicated to seeing it come to fruition.
It's exactly as absurd as it sounds, but the incest Illuminati doesn't cause any problems for the story. The real problems spring from the massive incel energy that the main character channels and its abrupt ending.
The incel bit isn't immediately apparent, but it really shows itself as the story progresses. The main character's defining characteristic is that he's a nice guy. He's 22 and going to school, but doesn't appear to have anything in mind for the future as far as a college major or job prospects go. His focus is on competitive video gaming, but frankly that content could have been cut from the story for as much focus as it receives. He never actually pursues any of the love interests, allowing dumb luck, the Complex Society, or the girls themselves to bring them closer.
A lot of this is typical harem protagonist style shit, but it's the nice guy thing that's glaringly brutal. The main character's plan to romance the love interests appears to be simply be close by while the love interests live out their lives and hope they realize how nice a guy he is. Fortunately for him, four out of the five love interests in the story were used by men and discarded in some form or fashion, so they're apparently vulnerable to this plan. We're frequently shown their internal monologues and it's frankly nauseating the way they harp about how nice he is when they're not sex drunk from his multi-orgasmic dick.
Speaking of that multi-orgasmic dick, the story ends
It's brutally abrupt, absurd, and solves all the story's remaining problems with the subtly of a sawed-off shotgun.
While I might loathe the main character, the love interests are decent outside of their terrible taste in men. You've got the mom with intense mommy energy, the sister who's a huge bro-con, the slutty(?) best friend of the sis, the lonely teacher who can't get a man to save her life, and the classmate with a dark past. As seen in the images, they're all titty monsters, which is a little boring but acceptable. Their stories might actually be pretty good if they didn't all share the same note of "look at this beautiful woman misused by terrible men just waiting for a nice guy to save them."
The gameplay consists of a time-management scaffold where you scene hunt through a linear story. There's the set up for a lot of focus on the professional gaming scene the main character is involved in, but outside of a single scene for the teacher's story, it appears to have been completely cut. Don't bother grinding your stats once you win the local tournament. Also, pick a high-tier character because popularity doesn't matter. I think you need like $300 to complete the entire game's content.
Overall, Complex Society is a mess. There were a handful of scenes I enjoyed throughout the game, but they mostly involved the side characters, as big mommy energy does next to nothing for me and received a lot of focus. I like Koikatsu models, but I can't recommend this game to anyone save the most dedicated incest fanatics.