Expedition: general discussions.

Implementing this will be truly challenging. Especially if you include cyborgs and demons. The former will simply break down without repairs in low-tech worlds (unless magic is used), and how will demons survive at all in non-magical worlds? And how do you explain such a difference in technological development between different worlds, given the possibility of traveling between them? Surely there wasn't any benevolent altruist or power-hungry villain who introduced technology to the low-tech worlds? How can this be justified? The excuse that "the laws of physics work differently here" will require creating worlds that are too unusual and alien. You could, of course, play it so that what is happening in the expansion is essentially part of some strange virtual reality, but that is hardly what you want.