This VN is good. Really good. Visually, (besides the few clunky animations) its a 10/5. The renders each stand on their own merit artistically. Hell, I've seen people who only do renders who are lazier than some of the shots this dev makes. I just want to be clear that there are many things about this VN that are as near as perfect as you can get, but there are some really BAD things that I think the dev could easily fix if they wanted to.
Most glaringly is the influence that anime tropes have had on the characterization in the game. Apparently the dev team are actually japanese... which explains the "japanese" setting. If they want to make a VN with characters of varied ethnic background and say that its set in Japan, more power to them - or anyone for that matter. It's fantasy after all.
That being said, most of the japanese elements in this VN only serve to get in the way of the plot, or to make it entirely nonsensical. I was very surprised to learn that the dev team was japanese, because it feels like a weaboo dev is just inserting things he knows about japan haphazardly throughout the game with no rhyme or reason or real care for what it does to the overall story.
This VN has all of the elements that could make for an interesting and dramatic adult story - and it could still mostly be that with some minor changes. As it is though, all of the cast are suffering some sort of anime trope behaviours. For the characters who are supposed to be 35+ years old, this comes in the form of switching personalities back and forth, often multiple times in the same conversation between having a more complex and adult personality to being a character out of a teen anime. The women are mostly behaving like tsunderes towards the MC, and the MC is constantly switching between a grizzled 40yo cop and a stuttering 16 year old boy who is scared of his mama and gets constantly disciplined and told off by her, and who can barely handle the tantrums of girls half his age.
Nanami has also been inserted into the story much too early, and she has been slotted into the story in, again, a totally nonsensical way. She's the only ethnically Japanese character so far, and it feels like that's the reason she's been put into the story, just for the sake of having a big-titted japanese schoolgirl (see what I mean about feeling like a weeb wrote this story?).
She basically takes the role of what your daughter you've just been reunited with and have totally shrugged off should have done. For no good reason the story is written so that your daughter goes off to a modelling shoot with her grandma and aunt, even though she will just be sitting in a corner not participating. Meanwhile the MC meets Nanami and within a few minutes of knowing her is spilling the most intimate details of his life to her and treating her to more attention that he has his daughter so far. Later on Nanami is sleeping over and sneaks out of the room at night to see the MC and talk to him again.
Wouldn't all of that make more sense if Isabella was in Nanami's place? If the MC had taken more than a minute to try to bond with his daughter? To try to explain to her maybe the reasons behind why he left her for years? To give her something to latch onto as far as knowing about either of her parents? No. No, it's much better that the MC has done all of this extensive bonding with some random girl he has known for less than a day rather than with his daughter, who he's talked to for all of 10 minutes in the space of the few days that the game has taken place in.
Overall these things make for a messy and nonsensical story, and with characters who are totally unsympathetic and have incredibly immature and inconsistent characterization.