Paradoxically, this game feels both very polished and very rough.
The character graphics are fantastic. The animation isn't dramatic, but it manages to add so much to the expressivity of the characters. The UI is just super slick and polished, it fits the theme of the game and looks very nice. For the most part, the animation and sequencing work is superb. The journal at the beginning is a bit info-dumpy, but it's well executed.
The music is a mixed bag. I'm not sure about the choice of music for the menu scene, but it is very nice. The first song in game is nice overall. The second one is a bit of a weird choice, and it's too loud in comparison to the others.
The backgrounds are also hit and miss. The first one is clearly a manipulated photo, but it works. The second one (living room), eh, it's fine. The third one just looks like a picture and has a car from the 2000s visible on the right.
Story-wise, though, the whole thing feels like the first draft of the first chapter. I think you did mention it's a prototype, so that does make sense although the high level of polish in other areas makes it stand out. In the part with the explosion it's not clear what's going on- missing effects, maybe? It's even less clear why it's happening. I thought they were working for some institute, but it seems they're actually just doing this in secret, and competing with a science fair for access to supplies for their potentially world-changing technology? The intro text dump does a good job of explaining the what, but not the who or where. Everything also feels way too familiar for something set in the next millenium, unless it's meant to be a zeerusty throwback. It feels maybe at most 100 years in the future, not 1000.
All that being said, it is an intriguing storyline. As a hook it works well enough; despite my questions and reservations I want to learn more about this world and the story of these characters.
There's no gameplay at this point, but maybe it's supposed to be a kinetic novel. I'm personally not a fan of those but there's nothing wrong with them.
There are a few things that... I don't know if I would call them bugs or flaws, but certainly oddities. Nulla's portrait is in a different spot and it took me a while to figure out why. Dialogue has quotes around it. The Renpy button bar overlaps the journal UI (though it fits the dialogue UI nicely).
I always have a tough time judging unfinished games. There's clearly a ton of potential here, and some of it is already realized. This one is doubly weird because it's so slick graphically it makes the story feel even rougher- some kind of cognitive dissonance, I suppose.
I think it's going to be a pretty damn good visual novel if you can address some of the weak points, tighten up the storyline, and of course bring the whole thing to completion (which for me is always the hard part).
EDIT: Typos.