Well maybe a sort of planet map like mars or the moon. Also if uv ever seen the movie waterworld maybe something like that. If u havent seen it go check it out. Its post apocalyptic where dirt is the currency since the world is covered in water.

maybe a map that consist of 7 broken apart islands and in the middle this massive deadzone with a big sunken ship and watermines

add food, water and zombies on the map...its supposed be a zombie game...