I just finished it. It's really great. The artstyle, lore and world-building suits each other perfectly. All the characters, their design and the story feel like a mix between WW1/2 European/middle eastern history and Jugendstil. Which makes sense because Jugenstil was around WW1. Including the tid-bit, that is very important, about the refugees of a lost nation and their forceful resettlement hits home with me and I'm so glad that you mentioned it in a game about nations trying to eat each other.
I must say whenever an otome game pops up it's very rare that I find every of the LIs appealing or interesting. This here goes beyond "oh he looks nice I guess". They all have interesting and solid personalities. The dialogue flows naturally. Oh and all that lovely hair.... *cough*. Visually everyone of the LI is gorgeous and totally my type. You are really good at drawing expressions which also aid the characterization of a characters. They just really fit each of them. The amount of different sprites you've drawn for each scene is pretty impressive.
I'm very happy with the dialogue options we get presented with. Makes it hard to pick one, because they often all have their merit.
And sorry about blabbing about the LIs, but again... it's pretty rare for me to find an otome like visual novel were every male LI suits my taste. I like long hair and preferably no beard or even a beard stubble. Hah... You even gave them a banging personality and didn't turn them into idiots with no agency or goals.