What a great game! I personally need more normal visual novels like this, with all the sandbox AVNs popping up left and right. Great story, I loved it!
I do have to say, however, I am somewhat disappointed with the fact that most characters have their first and last name start with the same letter. Makes me feel like not enough effort went into thought process for their names, you know? Similarly, Kuro's last name containing "Kage", as well as Okami having that name is a bit on the nose. Regarding "Buki-buki": is that a wordplay on the main character's default surname "Ibuki"? I know it's a cute/silly nickname Miri gave to his gun, but to someone who speaks Japanese it just sounds like "weapon-weapon" and I don't believe that's something a native would call it, even someone like Miri, unless it does have that double meaning with MC's last name.
If you don't mind me asking, are you Japanese, Mr. Vertigo? Aside from the obvious cultural references, there were several nuances that made me think the developer might be from Nihon. I don't remember most of them, but it was stuff like someone exclaiming "Heee" when surprised and some similarly minor details.
I want to commend you for smooth phone usage with text messages. In some games you press PgUp while in the phone and it goes all the way back to when you clicked on the phone, in others it straight up breaks the game in various ways. In your game it works perfectly fine and that's something I appreciate very much.
Anyway, it may look like most of this post was a complaint with all the name stuff, but I hope you don't take it the wrong way; it's all minor stuff and everything that I didn't critique I have greatly enjoyed. Believe me when I say that Crimson High is one of my favourite AVNs. Thank you for making it!