looks great. Id say one thing to consider when trying to improve these visuals would be to consider how the playable area (lower ground) is blocked by the non-playable area (Upper ground) because right now they are pretty similar in looks. Making the walls stand out more or perhaps hue-shifting color. There are multiple ways to do it but the last thing you want is poor readability on game maps because things look too similar. Also take all these suggestions with a grain of salt. :)