Concept
Well, it's an interesting concept for a VN. I wouldn't bet anything on it finding an audience that you can't afford to lose. Video game genres are the way they are because of market forces beyond our control. Sometimes, an indie can create something new and get lucky, but I wouldn't bet the farm on it. Especially as a first project.
Visuals/Presentation
I liked the character designs. I hope that if it ever makes enough money that you can afford it, you'll consider hiring an artist to replace the AI art. It's fine for prototyping, I guess. And probably for the first release, too, considering how big a risk you're taking, bucking market trends.
Mechanics
I didn't notice anything obviously broken on the homepage, or in the game. (I assume that if you didn't modify Renpy's internals, the menus and such should function normally. I didn't test every possible button and save/load state, obviously.)
Tone
This ended up being a personal hang-up for me. I only played it as far as the guy in the suit introducing the teams. All the talk about religion and ethnicity started making me a little anxious. It made me feel like, "Uh-oh... This sounds like one of those TV shows that are only popular with people who already agree with the creator's politics." I realize that you're probably just copying the social cliques you see or imagine in your own school, but when you combine that with the lackadaisical, comedic tone, it starts to feel like dangerous territory.
My advice is to tread very carefully, if you're deliberately going for satire.
And if you're not going for satire, then maybe it would be a good idea to base the cliques on things that are the characters' choice, like what school club they're in, rather than on things like race, religion, or politics. Especially in these fraught political times!
Of course, all art is political, and your political views (whatever they are) are bound to end up in there somewhere. If you try to strip it all out, you'll end up with something bland. The trick is to embed concepts and principles, not details, from the real world. Less "Imperial Japan during World War II," more "The Fire Nation," to borrow an example from Avatar: the Last Airbender.
Make your characters interesting because of who they are as individuals-- what they do and what they believe-- not so much because of "what" they are, or where they came from.
Story
The bit that I played was an efficient way of introducing the player to the high-level concept, but it wasn't very engaging to read. (Other than my aforementioned visceral reaction to the creeping awareness that it might be teeing up a political rant, of course.) It felt very much like an elevator pitch. But since you're only asking about the concept, I suppose it did what it needed to do. Actually, I was a little fuzzy on this... is it about a VR video game, or a Death Game with real weapons? Right now the text supports either interpretation, unless I missed something.
General advice on improving
By far, your biggest help, going forward, is probably going to come from tutorials and videos about writing. I say that not because the writing I experienced was bad, but because writing is the fundamental core building block of any good VN. Focus on resources specifically for writers; the internet is full of them.
You seem to have an art pipeline nailed down, at least for the conceptual stage. I'm 90% sure it's AI, because the characters' eye shapes keeps changing, but I'm also sure that (locally hosted!) AI is the cheapest way to cobble together art for a first project like this, especially one with a potentially risky market fit.Making the concept 'cooler'
Start by replacing real-world factions (foreign students, religious groups, etc) with factions from your fictional setting. If it were me, I'd consider pivoting to something more fantastical, like a magic school, superhero school, something like that, so it's relatively quick and easy to explain the fictional cliques to a new reader. (Though that would necessitate a lot of new character designs-- definitely don't go to that much trouble if I was mistaken about the AI before, or if, gods help you, you're spending tokens on this.)
But if you want to keep it grounded in a near-future real-world, make it a University, and group the students by their majors or their intended career paths after graduation.
Engaging the reader's empathy
I get the feeling that, because it seems like you're setting up the weakest group as the protagonists, this is either going to be either some sort of underdog story, or else you're teeing up a subversion later on? And that's probably a load-bearing part of your plan, so I won't mess with it. Hopefully, you'll take a more character-oriented approach when writing the start of the actual game, of course. this high-level, almost 4th-wall-breaking overview is fine to get feedback on the game's concept, but if the reader doesn't empathize with the characters, you don't have a story, no matter how cool the high-level concept is.
Final Thoughts
Writing is incredibly subjective. I hope some of this was helpful to you. Good luck.