So many things to say, I don't know where to start. I really liked this.
I didn't like that the concert couldn't be replayed, it was nice the "you restarted" thing but I wanted to see it again so I deleted the save file in appdata. That opening song is so good, so beautiful, it was a joy to watch. What followed after that was spectacle and surprises, though not much that explained or advanced the overall story, but I guess that's the idea of this demo of the demo.
I think I understand the things that the story is going for, they look promising and well grounded. Although I wasn't sold on that thing where it was assumed that the player wants to be a pacifist all at once, I don't think it fits much for other players. By the way, is the beginning some sort of reference to how in anime games sometimes the male avatar looks more boring than the female avatar?
There are a lot of ideas and a lot of creativity, it's short but intense. How long did it take you to make the whole demo? Planning and preparing everything, it's amazing that you did this as your first game, it must have been quite a challenge to program everything you see in the game and make it look good.
I hope you progress well with your project, I want to see it complete, I liked it a lot. Cheers.