I was able to find a better laptop (i5-3230m 2.60GHz, GeForce GT 645M), run and try out demo a bit. Technically everything worked fine, I didn't notice any bugs or crashes, animated scenes ran smoothly, but being able to run game on potato laptop I mentioned, would be great.
As I mentioned before I'm huge Nagatoro simp, so I went through stories choosing only her as main girl. I was also interested in Kobeni's story, but I haven't gotten through that story yet, maybe I'll do that later. Here are the things I want to point out:
Text in stories: serves its function, not cringy and easy to read, but I wanted it to change a bit depending on girl chosen. From what I understand, right now text in stories is the same for all girls, but if it's possible to implement this, I'd like it to be character specific for each girl you choose. Maybe add special lines for each that wouldn't affect story as a whole, but are characteristic of each particular girl. Nagatoro teases her partner with sexual innuendo, but when a real sex-related situation happens, she becomes very shy and cute. It would have been nice if this could have been reflected in text of story. But overall, even text as currently implemented in demo is quite appropriate for her character, so I'll be fine if things stay the same.
Character sprites: using Koikatsu models as static sprites is great idea. There's no dissonance between animated scenes and novel, girl looks consistent everywhere and that's huge perk + I've always liked that Nagatoro model, so I'm just happy to see her used, both in static and animation.
Animated scenes: it has to be said that the costume choice for girl is a killer feature. It's damn nice to look at and I reran both stories 4 times each just to see Nagatoro in all costumes in all scenes. If it's possible, I'd like to see even more clothing options for Nagatoro. As far as I remember, this model also has competition swimsuit version and a demoness cosplay version, I'd like to see those clothes in game. It's also nice that all the costumes are involved in animated scenes. There was a desire to go through story again to check out how each costume is involved in animations. Poses and motion in animated scenes are good, but they are sorely lacking in sounds. I don't know how hard it is to implement, but even if it's one voice for all girls and standard sloppy sound, it would be better than no sounds at all, for my taste. Also, I'd like to be able to change camera angle during animated scenes. I think that free camera is too difficult or impossible to implement, but it would be awesome to be able to select one of several predefined viewpoints in animated scene, it would greatly diversify view and add interactivity.
UI is easy to understand and not bad looking. Music is good, but it would have been nice to add tense melody to NTR story, from about midway through the story, at the point where it becomes clear that this was a very bad idea...
I guess that's all I wanted to mention. Sorry for delay in leaving feedback, it took me a long time to get to a better PC. Hopefully development will go smoothly and I can see some updates and new content soon (preferably Nagatoro related lol)