The island generation is ripped from an old (OLD OLD OLD) modded terrain generator. I picked a piece of terrain I thought would work and then swapped a bunch of blocks and added my own layers and procedural decorations. Most of the overworld and the sphere designs were done as quickly as possible so I could get to the command blocks, dungeon layouts and mechanics.
Also (unrelated to quoted post) I have released beta version 0.1.13!
I think this version is pretty much a release candidate as I'm not getting any feedback but, having played the beta several times myself,I think it plays just about how I want it.