At the moment, the game feels a bit depressing. The background is dull and although the music is okay, it doesn't help with this.
I get that you were going for a 4 color palette but in my opinion, you should have either used a brighter palette or used the brighter colors for the icons while leaving the dull ones for the UI.
I do like the concept,sfx and design though except maybe change the province display to be more organic? I understand that its hard if you're not particularly good at art but you can just randomly place the rectangles around or in a brick laying pattern.
It would also be great if you presented the tutorial a bit better since its an important aspect of your game. Walls of text might deter people from trying out the game.
I hope you keep making games!