Don't you like her?
She's a cutie. I'm hoping we can get on better terms with Lucy further down the line, though. I'm torn between enjoying pushing the submissive tsun against the door and missing the genki oneesan energy she had when we first met her.
Some of the grammar is incorrect, but the overall dialogue quality ranges from servicable to good. The only concerns I have with the writing are player agency and dialogue choice transparency.
Player Agency:
Obviously this is a very early alpha, but the game feels pretty linear. I'm not sure how much agency is really intended for the game as a whole, but I will give my caution anyways: giving the player the opportunity to express themselves through the PC only to ascribe emotions and wrest control from the player can sour them quickly. For example, let's say you're playing an incest game with a younger sister character, and you - the player - have consistently made choices to be kind, loving, and protective. Then, a scene happens where the MC comes across the sister showering, and the game describes the MC as suddenly being overtaken with lust. Without the player's input, the MC sneaks into the shower and begins huffing his sister's panties until she steps out the shower and freaks out. Somehow or other, this forwards the plot.
This is, in my opinion, a capital crime for a VN. It has lesser brethren, like the MC having a radically different personality in interactions with different characters. So yeah, friendly advice, take care to have a consistent approach to characterization and player control. I wasn't really put off by the way the MC acted with Lucy, but I was surprised that so much of that happened out of my control and that the MC seemed to enjoy it.
Dialogue choice transparency:
There were a couple of options that I thought were meant to be humorous, but the actual dialogue was more aggressive than was indicated. When Mia brings over the DnD game and the MC is asked if he knows anything about the game, one of the options is simply described as "Read the title." The MC reads the title, "Dungeons and Dorks," and then continues to say "What a stupid name." Woah! Not what I intended at all. It's frustrating and it pushes players to choose the "safest" option when given a choice. If you want an example of a game that was harshly criticized for this, checkout the discourse on Fallout 4's dialogue system.
Some simpler pieces of feedback:
The environment is very bright and some of the characters' floating text - especially Lucy's - blends in too much with the background during the day.
An FOV slider would be nice.
I like the feature where text floats above characters' heads, but shows up on the bottom of the screen if you're looking down or away from them. I think that the tolerance could be loosened up a little bit though; it's pretty easy to point the camera at a vertical angle where I can't read the floating text but the game won't switch on the text on the bottom of the screen.
The game looks really good though; one of the cleanest 3D games I've seen here and the animations/expressiveness of the characters is awesome. I was impressed by the early conversations with Sarah, and the face-off with Lucy at night was a scene I'd experienced in other stories before but it felt so much more intense in a dynamic 3D environment. I'll be paying close attention to this one and I wish you the best of luck.