There are two systems for interface zero. Savage Worlds and True20. In order to provide an answer that fits both concepts, I shall be vague on mechanical details.
The genre of Interface Zero is summarized thus:
What is Interface-Zero?
Interface-Zero is the True20 cyberpunk game from Reality Deviant Publications, combining elements of classic cyberpunk, post-cyberpunk, bio-punk and a touch of Japanese anime.
The world of 2088 is filled with adventure from the formerly-United States of North America, to the state run business arcologies of the New Chinese Mandarinate, from the Deep Net, to deep space and beyond.
The first commandment when running a game that you and your players are unfamiliar with is: Simplicity, simplicity, simplicity. Blatantly steal a plot from a novel. Looking at the TAP, my first thought is to steal the plot of Vernor Vinge's Rainbows End. It's trivial to adapt that world into cyberpunk, and offers a refreshing take on augmented reality separate from the one that the more traditional books (Shadowrun, for example) offer.
Don't start with a campaign. Start with a series of 1-2 session games designed to familiarize everyone with the rules and the settings. Run a game with the TAP, run a game with Corporate Espionage, run a game in the Sprawl. Encourage your characters to make throw away characters for each of these.
Once you've calibrated the groups' expectations and formed either an implicit or explicit social contract, sit down with your players and ask /them/ what they want their game to be about. If you've run vivid (yet simple) games, there will be aspects that have "hooked" them. If they want to be part of an organization, let them forge the history of the organization through a game of Microscope. Especially with cyberpunk (with its many options for "naah, we don't want to do that", you are at your players' mercy, and that's the best way to have it.
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Rough Campaign Map
The Curious Case of Edwin Rashomon
Roughly modeled after Rashomon, it's a great way to have the players explore a scenario with different characters (across multiple games) but a consistent theme. Watch the movie first.
Act 1: The court case, an exploration of a TAP enabled crime scene.
This first game, players will be corporate types, hackers, tagging crime scene for a criminal case. They will chat with the various investigating officers, and play with the TAP rules to create a scene for the court. You'll want a hacker, an icon, and a technician at least, and play them off the competing lawyers.
Act 2: The Husband's tale
The bodyguards and troubleshooters of the husband. They'll explore corporate politics and some troubleshooting. End the act with the encounter with the bandits.
Act 3: The Bandit's tale
Gritty gangland. A gang, taking the role of the bandit, doing shady work with their own views on what really happened. End the act with the encounter with the husband and wife. Make sure that the players can play the encounter out the way they want to, identical results are not very interesting.
Act 4: The Wife's tale, reconstructed
TAP and hacking. Get a visual reconstruction of the event from the wife's implant and associated devices. Lots of hacking, some palm-greasing. End the encounter with explorations from different feeds, presenting the wife's view.
Act 5: The court case. Let each player take a different side and have them argue it out.
This is designed so that you can show the players many different and vital aspects of the setting around some consistent narrative, but it may be a bit ambitious.
The scale and power of the Big Ten should not be undersold. Nor should the power and insanity that one experiences with a Horror. Shadowrunners are just a bunch of dudes, really. They're just really good and professional dudes. Ticking off the different corps or governments of the world can and will buy retribution from those corps if the cred is enough. And having the prison being a major hub of the players and where they are kept, there's a really good answer to this.
Have a mega corp purchase the Shadowrunners.
Honestly, this is the natural progression of your game. You are having the runners hit a Karma level that screams retirement or world-changing efforts. They can't continue to play as random chaos anymore. They are too powerful to continue to ignore, from a mega corp standpoint, and are good only two ways. Theirs or dead. The runners have shown Saeder-Krupp that they are good and can piss off a great dragon. If I was running Lofwyr as a business man, I would see the potential that these runners could offer, given that I could buy and contain them. Else, I'd just buy them to have them executed to get them out of my hair. As a great dragon that's in charge of the most profitable Big Ten in the world, I have so much cred that I can throw at a problem, I might as well bury the players in mountains of it to suffocate them.
Really, the best you can do at this point is show the runners that they can't be ignored anymore. No matter the power level of a PC in Shadowrun, there is always something bigger, tougher, and meaner. I'd go so far as to tell you to sic a cyber zombie or two on them. Not the player driven ones, but an honest to god walking abomination of magic and technology. From the flavor of the game and the durability and deadliness of it, it's the perfect thing to send at the players if you want to test them at this point. And most corps can claim to have one in their back reserves to clean up messes like your Shadowrun team if they absolutely have to.
But even if they can down the cyber-zombie, there's still the question of where they go. And honestly, I think it's time to roll new characters. A year-long campaign that's sprouted a few 250 karma players means it's time for a change of scenery. Have the runners take on their last challenge, break free from the prison they've been in or die trying, and retire the campaign. Keep all the flavor, even put some of the old PC's in as NPCs in the world if they survive, and roll up new characters. It's the kind of thing I see and say "It's been a good run, so let's go out in the biggest bang we can and start fresh". But, again, that's my two cents on if I was running the game.
Best Answer
Wow! I'd suggest you go again through Pat Garret & Billy the Kid, Butch Cassidy and the Sundance Kid, the Good, the Bad and the Ugly, the Magnificent Seven and OK Corral and then plan the appropriate end of the campaign!!! Of course these movies will give you more a mood and inspiration, rather than straight material....
I think you should tell them (informally, out of the gaming sessions...) that the campaign is heading fast for a Grand Finale, so they'll come with the right attitude.
They will have a number of patterns to choose: maybe the'll turn against each other, a bit like like the Good, tha Bad and the Ugly, or maybe they'll go for a common good cause against an overwhelming enemy (Magnificent Seven), or maybe they'll have to escape from an overwhelming enemy that eventually will catch up with them (Butch Cassidy and the Sundance Kid - I'd recommend this!).
At the end they'll probably all die and in next campaign that you'll prepare (quite a lot of years later, in the same world) they will be mythical / legendary beings and great stories with unexpected twists, falsifications and embellishments will be told about them.
During the playing session I'd put some special music (given the inspirations, probably Bob Dylan's songs for Pat Garret & Billy the Kid + Knocking on Heaven's door... or Ennio Morricone!)
Enjoy and let them bow out in style!
have a look at this picture.... do you remember it? ;-)