Thanks for the comment. I'm glad you liked the aesthetics. I meanly went with the black and white look, because as part of the game jam this was made for they had extra challenges and one of them was to only use one color. This also allowed me to spend less time on the art and more on the programming. Because of the time constraints I didn't have that much time to balance the game, I wasn't able to find a way to force a more interesting trade patterns. I am not really happy with how the difficulty works, as that the game gets easier the longer you play.
As for the bug, this was one of my first programming projects so the fact that you only found one is good. I even found a few that I have never seen before today when I was looking at the code.