Yeah, the writing is definitely...
I'll skip complaints about the general spelling and grammar (which, to be fair, is not good) because the only real advice you can give there is "get better at English, or find an editor who is fluent", and jump into the more foundational, structural stuff.
First, two things the writer does well so far. Except for one case I'll get into later, the characters are well-defined. I know who they are, I can tell them apart, and they all seem to serve some kind of purpose in the story. Also, the scenes all serve a purpose either in moving the story forward or telling us something about the characters.
So the skeleton of the story is all there, where it starts to fall apart is in the execution.
The thing that hit me was the egregious info-dumping. The writer has obviously put work into building their setting and characters, even drawing attention the depth of their research in the game's description, and can not wait to pass that information onto us, the players. We can't just see that the main character is short by, well, looking at her on the screen, we have to be told she is exactly 5'2 and that this is a normal height for women from her country. We can't just see her wearing a dress, we have to be told explicitly that it is Batik, and get a potted history of Batik and its prevalence in different cultures. We can't hear that a character is from Thailand, we have to know that Thailand is a lot like Myanmar (also known as Burma).
It's OK not to tell your readers stuff, if that stuff isn't explicitly relevant to the story. It actually makes your writing stronger if you include details like culturally appropriate clothes and food, or accurate geography, quietly, without dragging the reader out of the story to explain them. If the reader really wants to know what Mote Lone Yay Baw is, they can always google it.
So whenever you're about to impart some information to the reader, ask yourself if there's a reason in the story for the reader to be told this now. If not, maybe they can find out later at a time its relevant. Or maybe they never need to find out at all, it's just a background detail you keep in your head that influences how you tell the story.
One way to combat this is to kill the narrator. Narrators are hard to get right in VNs, and authors really should think twice before allowing them any role more complicated than telling the reader where they are or what the time is. In this game, the narrator feels like another character, specifically the voice of the author, and they're the one character in the story that has no reason to be there. In the middle of a scene they'll tell you a character has beautiful eyes, or let you know something they read on Wikipedia. Which is really awkward because the last thing you want when you're watching porn is some stranger looking over your shoulder pointing things out.
Instead, for each scene decide from which character's point of view the story is being told. This is the only character's thoughts we have access to (don't swap between characters mid-scene, it's hard to do well). Is the exposition you're about to write something a character in the scene would naturally say, or the POV character would be thinking or feeling at this exact moment in the story? If so, go for it. If not, throw it out.
If there's something the reader absolutely has to know right now, and it doesn't fit, find a way to make it fit. Move the scene around until it is something a character would say, or the POV character would be thinking or feeling. That way the information gets delivered in a way that feels organic and part of the story, not a footnote to it.