I only had one chance to run a PA game so far and I didn't know if my players would like it so I went with everything.
The PCs started at first level. The campaign features magic, AI, aliens and everything else I could think of.
The short backstory is that in 2069 after all the oil sources were depleted, the European Union, the USA (allied with Canada and the South American United States - SAUS), the Soviet-Chinese Union, the United Islamic Caliphates, and the African Federation of Tribes declared war on each other and used nuclear weapons, robot soldiers, and special human forces in order to destroy each other and the world.
What they did not know that an alien mothership gave the AI and the cheap robot technology to the humans (with a backdoor in the very foundation of the AI for them to control all robots).
What the aliens did not know is that the AI controlling USA's defense (curiously called SkyNet for no reasons) learned of their existence and it swayed other AI to help him to bring down the alien mothership. In the calamity he shot multiple nuclear warheads at the mothership which made an emergency landing somewhere in Asia.
So we have aliens and robots at this point. Magic? Mutations?
Magic is the power of the brain. Acolytes use their extreme beliefs to create miracles, Mages use power of the logic and only Telepaths or Battleminds know that they utilise the powers of their minds.
Mutations are mutations. Since this is a fictional world I rule that PCs could get "beneficial" mutations as well from radiation or mutagenic compounds. (not only cancer)
I personally believe in a campaign evolution. What the PCs achieve in this campaign, affects my next campaign. So if they let the Japanese Empire (which was unaffected by the background radiation thanks to the "Japanese Miracle" that uses nanotechnology to clean radiation) win the next war against USA (which has only one city left, the enviromentally sealed Mega City 1 where 40 million people live and which is controlled by a lunatic) then in the next campaign the world economy will be ruled by the Japanese Empire. (thanks to the Japanese Miracle).
On further request I'll post a more detailed timeline
