From KickStarter page:
Inverse World is a setting for use with Dungeon World or your favorite fantasy RPG. It is a world turned upside down and inside out, the insides of a hollow planet. Inverse World could even be right inside of your very own fantasy setting, if you just dig deep enough.
Inverse World is an attempt to make fantasy fantastic again. It’s a break from standard. Notable features include:
• Mobility. Inverse World is all about mobility and motion. Some of the playbooks are capable of flight from the very beginning, and the others are highly mobile in their own ways. The world is full of floating sky-islands and cloud cities, and how you get from place to place is important.
• Exploration. Inverse World is all about exploration and adventure. Your greatest danger is the geography; your greatest treasure is seeing all of the world’s unique wonders. Inverse World dials down on the dungeon crawls and combat for action-packed exploration.
• Culture. There are no traditional fantasy races in Inverse World, no world-spanning monocultures. Sola’s children are all one people, yet still exhibit a variety of magical and amazing features.
Inverse World has its own set of six playbooks. They are as iconic and integral to Inverse World as the Fighter, Thief or Wizard are in Dungeon World.
• The Captain, a high-flying airship owner
• The Lantern, a warrior-diplomat of the sun
• The Mechanic, an inventive sort with a technological wonder
• The Sky Dancer, able to swim through the sky
• The Survivor, scarred from the aftermath of their cataclysm
• The Walker, a master of parkour and acrobatics