At first, 'Homonculus' seems to be pretentious. The titular creatures are merely manifestations of a person's psyche which only Nakoshi can see when he covers his right eye, taking the place of the person. This is a fine idea, but these homonculi are either very obvious in their symbolism or they will be explained by Ito. However, where this becomes more interesting is when you realize that homonculi are not only a representation of the person who Nakoshi sees, but Nakoshi himself. It's a statement on how our perception of others is inevitably formed by our own experiences, and the scenes I find most intriguing are formed by this understanding. The last section of the manga has a lot of sections that feel more like a representation of Nakoshi's perception of others than anything else. The ending is a great example of this, where there's a lot of ways to read exactly why Nakoshi sees his own face on everyone else now. Has Nakoshi found the connection to others that he wanted, or is this a reflection of narcissism? I think either could be a pretty valid reading of the moment. I also grew to like Ito far more than I initially anticipated, and his relationship with Nakoshi becomes pretty interesting.
That being said, the first half of this manga is a bit inconsistent. I think the creator was still considering what direction to take the manga. I already mentioned how the series is too eager to explain some symbolism, but the actual stories themselves aren't particularly great either. One story arc in particular doesn't contribute much to the manga and is a clear low point for me. It's about Nakoshi trying to help this teenage girl, and it feels the most like a bad seinen: edgy for no reason, with a somewhat hateful message at the end regarding abuse. One could argue that the teenage girl enjoying abuse from Nakoshi is merely his perception of the events, as Nakoshi himself has been superficial, sexist, and abusive at different points throughout the manga. However, this would take a decent amount of justification regarding Nakoshi's mental state to really make sense. For me personally, it became clear at some point (likely when he drilled another hole into his head by himself) that Nakoshi became truly crazy. That being said, Nakoshi still helped people with his power of insight in a way that wouldn't be possible if he was just crazy. Again, one could argue that this is just him believing he's helping people, but when the line between reality and fiction are blurred with no way to tell between them, the difference between the two becomes meaningless. At least for most of the manga, Nakoshi is supposed to be seeing reality so long as his right eye is open, and you could probably argue most flaws or oversights are due to Nakoshi being an unreliable narrator, but what matters is if it's compelling.
However, I like the series overall. If the entire story was more similar to that last half or so, I could see myself rating it much higher. Maybe I'll like it more if I reread it, but it's a pretty good series regardless.
