Many faces, one purpose - Unity, the oppressive authority you have fled, has followed you to Andromeda's Edge. Multiple Unity leaders, ranging in difficulty and tactics, will face of against your sole faction in solo mode. Or increase the risk in a multiplayer game by adding Unity into the mix.
 
The Escalation expansion provides pieces for a 5th player, two new factions (Nebulon Cloudpeople and Darkstar Acolytes), as well as a robust solo mode.