There is no Sky - Building a history of how a distopian scifi world came to be
I am in the process of making a game. The present day of the game is where the narrative will take place, which has a number of themes, but the easiest to latch on to is the overthrowing of an authoritarian ruler.
The Past: Even though my story takes place entirely in the present, with only a few references to the past, the origin is important and gets revealed near the end of the story. A massive city size space ship launches from Earth. It is intended as a utopian society on a multigenerational ship in search of a new habitable world. The ship has 8 floors (bottom 00 - top 07)and a massive central elevator which facilitates and encourages movement between floors.
The floors don't have a particular focus, except the top floor. 07 is the observatory, which people are encouraged to visit. Because the ship was going to be traveling for such a long time, the use of window-like materials was limited to the observatory. People were encouraged to visit to see space and think about how they were working towards a better future.
One other floor I will call out because it is relevant to the story is that on 03, the middle floor, there is a sensor room which is constantly scanning in search of a habitable world. Similar to the observatory, people are encouraged to visit to give them hope of finding a new world.
The Present:
The present is rather grim as dystopias should be! Over 10,000 years have passed since the ship originally launched. I will be describing the world from the point of view of an average citizen, and touch on exceptions when relevant.
Not just the mission, but the entire concept of them being on a ship has been lost to time. For those living in the city, it is the world. Reality stops at the walls. They are the edge of existence, and there is nothing beyond them. Interestingly, some Earth concepts that don't make logical sense have persisted but feel more like fairytails or products of the imagination. The sky quite literally does not exist for them, but it would be understood, much like the idea of a sky island. We know a landmass cannot simply float in the air, but we know what it looks like, and there is something magical about it.
The Past:
The central elevator has long since collapsed, long enough ago that people don't remember it existing, though there are some signs of it having existed due to the massive hole left in the wake of its collapse. Navigation between floors is still possible, but it is difficult to go up floors. Doing so would require special permission, and IDs are checked regularly, especially at transfer points. The general population believes there to be only 7 floors (00 to 06), and each has a very defined role.
Going floor by floor:
00 - The bottom floor has been abandoned by authorities and turned into essentially a penal colony. People in 00 are referred to as Zeros (derogatory). If someone is sent to 00, they have their ID taken away and their identity is marked "Ceased to Exist". On the floor itself, it is mostly run by gangs who control resources like limited water supplies or the salvage exchange lift. The salvage exchange is the one place where interactions between 00 and the rest of the city occur. Raw materials are exchanged for resources or currency. Occasionally, people will be smuggled up to 01 using this salvage lift, but it is neither safe, cheap, nor easy to do so.
01 - This floor is focused on unskilled labor, primarily focused on materials processing. The conditions are rough, population is very dense. There are also some areas where people who got out of 00, or the children of parents from 00, tend to live. These places are semi-frequently raided by security forces, with anyone caught being shipped back to 00. You are likely to find underground businesses that also exploit the general poverty of the area, and especially people from 00 who can't find normal work due to not having IDs. Where the elevator shaft used to be, there is now a massive hole. It is used to send people to 00 and is also often used as a place to dump waste.
02 - Moving up, it is slightly nicer, but not by much. This floor focuses on slightly more skilled labor and on food production. Similar to 01, the elevator shaft is a large hole and is used for similar actions.
03 - As you continue to move up, living arrangements continue to get slightly nicer. This floor is where most security forces live, along with middle management. People from this floor are the most likely to travel to other floors either because they need to oversee what is happening on a lower floor or need to take security actions. I have toyed with the idea of a monitoring station on this floor that reviews system-generated risk ratings. Security will act on risk ratings above a certain threshold. If the risk rating exceeded that threshold by too much, they would need to get authorization from a higher floor before acting, especially if it required moving up levels to respond to the risk rating spike. Of note, the scanner room is on this floor. However, it has been blocked off behind a locked door that has not been opened in thousands of years. It is not under any security; it has simply been forgotten about. This is the last floor that has an open hole where the elevator shaft is an open hole. The security forces will sometimes use it as a way to transit quickly when using flying vehicles.
04 - You finally start to see small bits of (non-food) vegetation in the form of a few trees and bushes on this floor and individual homes as opposed to apartment blocks. The residents of this floor fall into upper management and the knowledge class. Either they manage several people from 03, or they have a scientific research role, or something similar. The elevator shaft has been covered and is instead just a central part of the floor.
05 - The elite live here. They predominantly oversee upper management and knowledge class individuals. Homes are larger; it is normal to have grass lawns. They also have trees and bushes as you would see on 04. Again, the central hole has been covered with a monument erected in the center.
06 - As far as the general population is concerned, this is the top floor, though almost no one is able to actually see it. There are very few people who live on this Executive level. The executive level is by far the nicest. In addition to all the greenery, you will see flower gardens and the occasional water fountain. This is also the floor that the High Captain Administrator (president equivalent) resides.
07 - I thought you said it didn't exist? That is only for the general population. This has become the personal office of the High Captain Administrator. Even the executives don't know this is a floor. Few, if any, other than the High Captain Administrator or those the position will be passed down to have seen this floor for thousands of years. As before, there are windows to space. There are a few other noteworthy features. There is a captain's log where the High Captain Administrator will record their thoughts, and can listen to past logs (this will be a bit of a lore dump for players). Not only does the High Captain Administrator keep it a secret that they are on a ship traveling through space, but when our protagonist and crew eventually break in, they look out the window to see that they are orbiting a habitable planet (and have been for thousands of years).
I am happy for any thoughts or questions about the past or present, but **what I would really like is thoughts on how I can fill in how the world got corrupted over time**. Right now I have general thoughts like shortages led to a crisis and a lockdown, some external environmental factors, and a fear of losing control from those at the top. I will note that while they may be misguided, the High Captain Administrator believes they are doing the right thing, and they have for generations (the logs will show that it has not always been an easy decision).