Nice visuals. When I see games with this art style, I automatically expect certain village-themed background music. But it was quiet. Does the game has sound or maybe my computer just not play it?
Interesting way to tell a historical event through postcards and dialogue of the persons involved.
I would suggest giving a one-liner description/title of each postcard when you buy it. The first thing I've got a postcard in real life is to flip it over to look at the back for its title/description, which would pique my curiosity to find out more about it. That one-liner could served as a title to the full text segment related to the postcard you are going to tell in your game. It's like...when you read a story or a chapter, it feels a difference with or without a title.