My world is that of a humongous cliff and pretty much nothing else. I was unable to be a flatlander so I justified it by making a humongous alien artifact and jabbing it into a polar region of a gas giant with a density of Saturn.
(Yeah, I suppose the star wouldn't be able to be so high above the cloudline... Perhaps it's an orbital mirror.)
It is positioned above the ambient density of the gas giant, and it is dotted with "emitters", that spew out air and moisture, keping the air pressure leveled out and breathable for a wider band of the structure than it would otherwise been (I needed hundreds of kilometers wide band of habitability, but naturally it would be more like just a few kms before the atmosphere becomes too thin to breathe.) I was thinking about how the atmosphere might work on the structure like this, and came to this setup:
There are several bands of air zones:
Zone A is where the temperature and the pressure of the air drops too low for life to exist.
Zone B is where the oxygen levels and the pressure optimal to be roughly earth-like.
Zone C is where all the air and stuff from above begins to be compressed by the gas giant's own atmosphere, it is unpleasant, hot, and dark down there.
Band 1 is close to the surface that breaks down the air flow, and it is a quite turbulent zone with relatively unpredictable winds.
Band 2 is the transitional zone, where the air currents are relatively uniform and calm, flowing outwards, pushed away by the air generated by the emitters.
finally, there's band 3, where the air generated by the structure begins to mix with the unbreathable atmosphere of the gas giant, and due to it being more dense than it, falling down into the abyss, forming a rather strong downdraft that drags everything caught there down with it and forming a wall of clouds on the outer side in a sort of reverse eye of the storm fashion.
So if you go too high, you'll freeze, if you descent too deep you'll be crushed, and if you'll stray too far from the surface you'll be caught up in a downdraft and dragged below, where you'll be crushed. This should nicely box the inhabitants of the slope close to the surface, by limiting where the airships can relatively safely travel (The green area), preventing them from straying too far from the surface and realize that it is not in fact a flat wall (Up close enough it's uneven structure should be hiding the curvature rather nicely).
I imagine that bands 1 and 2 would be rather thin, extending outwards from the surface of the structure to no more than a few kilometers.
So, does this makes sense? The game I'm doing this for isn't intended to be hard science fiction (it's a steampunk platformer (Justified by the setting to be a platformer!) with "magic"), so if it isn't entirely lines up with equations, that should be fine by me.