Campaign world idea... Flipped coin

[Tonguez]

the water pouring off the sides is vaporized as it falls forming a cloud dome around the lower side of the coin, held in place by osmotic pressure. The vapour dome is notably saline and ths creates an electrodialysis effect which manifests as spectacular ionic storms across the vapour surface. The upper (sun) dome witnesses this effect as an aurora around the perimeter of their world layer. The ionised vapour dome is also affected by volcanic and other weather affects above and may indeed be the source of magic on the surface.

The ionised atmosphere of the vapour dome produces enough of both energy and breatheable air for life on the lower surface to thrive. The life is very different from the surface being based primarily on mushrooms and algaes including large terrestial plants related to seaweeds. Corals and Riptide horrors that are found in the deepsea above have emerged onto land on the lower sphere

 

[wlmartin]

I love all these ideas
The idea of it tilting, is a great one... it could have some kind of low spin that causes it to tip at the flat axis a bit

Maybe use something that grows in the dark, like mushrooms, as the basis for the ecosystem. Also don't forget plant life growing in the oceans producing oxygen. Geothermal vents and lava flows could also come into play.

Dwarf Fortress... yay

All great ideas

Lots for me to think about... its amazing to me that I really want to get a new D&D game started but i want this new world to be unique and powerful enough that im not disapointed once i start running it.
I could just pick an idea and run with it but this part of world building always strikes me as the most creative so i want to give it its time.