The Planes is one of the games I'm producing. In fact, I'm also coding it.
It's a top-down RPG game. The world consists of several dimensions (or "Planes"), each of which extends infinitely in all directions. Terrain is procedurally generated. Houses are procedurally generated. Everything is procedurally generated.
From any Plane, you can travel to a higher or lower Plane. You begin on a midieval Plane called Erde. The firey underworld below is called Unter, and the etherial cloud world above is called Luft. Legends say there are planes beyond those.
Anything you find in a Plane can be picked up (houses, trees, animals, NPCs, etc.). Houses are bigger on the inside than on the outside. Your house serves as your inventory.
Expect a Kickstarter for The Planes in early 2017.