Everything blue is underwater. Craters replace mountain ranges and valleys. Nearly all islands are rings around massive, circular lakes. The gray areas represent the highest elevations, and in that area on the eft of the map you could have hundreds of isolated cultures/habitats, cut off from one another by steep, round walls.
And of course, there's the question of what caused all these craters? And will it happen again? Is it happening now?
The more-than-sufficient low-rez version is here. There's also a high-rez version where you can count the buttons on the Moon Prince's frock coat.