From the designer:
Just outside the center of a lenticular galaxy a gas giant spins slowly around a dying star, holding five moons in its embrace. The natives of one of these moons have named their world Acheron, and their civilizations have risen and fallen for tens of thousands of years in the porphyry shadow of this Goliath. They worship a multitude of gods and debauch themselves in the ruins of their ancestors; outside the walls of their cities savagery abounds, and great treasures lie buried beneath the wreckage of time. Do you and your Band have what it takes to wrest these riches from the wastelands, or will you join the multitudes that lie beneath the rotting stones?
The Totality of Ygg is an OSR rules variant - "Dungeon Master" friendly, medium "crunch", old school feel.