Nobody really cares about the world outside the Dark City. You can take the tube to other places, but few do and details are sketchy. Technotown is nearby and significantly different in style; sometimes Rat Critters from Technotown flee to Dark City. P-Max is a popular porn soap by Pontifex Corp. Those who can afford it access it virtually through Pontifex Net. Other than that, the surroundings are a mystery. Everything you could ever look for exists somewhere in the Dark City. Unless you look for free, empty space. Whatever that is.
Sure there are other cities. You go there by tube. A friend of mine visited one once, it looked mostly like it does here.
Levels are numbered, with the lowest numbers at the bottom. The campaign starts on Level 51, the first level below the Corporate Levels, which go on in increasing opulence to about level 90. Levels below 50 are Slum Levels; levels below 20 are legendary Underlevels, inhabited solely by monsters and robots, if Urban Legend is to be beleived.
The corporations rule the world. They are huge and impersonal, but neither good nor evil, really.
I'm with a Punk Gang! You gotta' show me respect! The gangs rule the streets in the Slum Levels and lower Corporate Levels. There are too many gangs in Dark City to describe them individually, but it is good to know of a few types.
Chi Energy can be channeled in a variety of supernatural ways. It is very real, but it has mostly adopted to technology and turned into Technomagic. Real arcane magic is rare and dangerous. Most Technomagicians are rather weak, and punch the corporate clock or turn to a Coven Gang for protection; a few are as powerful as entire corporate magic divisions and can raze city blocks. All are considered dangerous ant controlled as thightly as possible by the Men In Black.
Psionics is a side-effect of Cyber Tech. People who have had their natural Chi Energy disrupted sometimes channels it into psionics, and become Psiborgs. Natural, living psychers are almost unheard off. Any evidence of psionics is quicky investigated by the Men In Black.
There is no such thing as a Technodemon. Corporate magic is perfectly safe, and the Men In Black handle all extraordinary cases. Any unexplained events are caused by a Coven Gang or Booster Gang. Return home and lock your appartment door, please.