That doesn't tell me all that much honestly. You can't really be worried about spoilers when discussing the fundamental worldbuilding; that's fairly high on the list of things relevant to interested parties. In such case let me ask for a few specifics.

[i]Tech base?[/i] What indistinguishable-from-magic devices are considered standard? What is considered bleeding-edge?
[i]Playable species?[/i] Its suggested that there are more options here than just what's been presented. is that a "make your own alien" type deal, or are there additional prefab species hashed out?
[i]Relevant powers?[/i] You talked about an alien collective, the remaining human population of Earth, and a third non-human species at odds with that collective. Would there be these powers/factions represented within the area the player characters inhabit and do they play significant roles in that area?

These are the kinds of questions I require answers to write a character, write for that character, and even assess if this is something I want in on. You're welcome to keep this under wraps instead, but it's at the risk of being too enigmatic for me to join.