what irk looks like

Oooh, this is neat. I'd imagine it'd have more lights and obnoxious glowing advertisements though. Also, imagine historical Irken cities being built using massive limestone caverns on Irk as a base, right when they were first industrializing. Towers and towers of metal buildings and wires weaving in and out of and built around the natural rock formations of the cave, towers of apartment blocks reaching up towards the cave roof. Of course, most of the natural rock formations aside from the ones holding up the cave are gone in these caverns now-the Control Brains decided they could use the building space.

Of course, some of the older smeeteries are still built like this, and there have been more than a few instances of smeets wandering off into shafts no adult Irken could squeeze into, not even a table drone, and disappearing forever. There's also rumors of a society of feral Irkens that originally escaped from smeeteries, and a subspecies of subterranean Digestor, but none of these are confirmed.

The post of cities from Blame! and NaissanceE made me think-we've only seen above-ground Irken architecture so far (Irk, Devastis, Foodcourtia, Conventia, The Massive) (other than the smeetery shown in the flashback for Parent-Teacher Night), and all of the above-ground examples are public buildings, meant to be seen. What if there's an entire separate half of Irken architecture (maintenance shafts/tunnels and such) that isn't meant to be seen by the public, and so has no effort put in to its design other than having a functional structure-no decoration, no advertisements, no lighting (you have your ocular implants, you don't need lights!), no nothing-not even the pink and purple colors Irken architecture is known for.

the reason both blame and naissancee bring IZ to mind is uh... the tubes. the cubes. the grunginess of it. well not naissancee thats like unnaturally sterile. but the grungy industrial look is (chefs kiss)
and on a bit of a tangent ive been meaning to study grungy art styles like this, esp the backgrounds, because honestly? backgrounds are good we need more of them

The underground and spacefaring Irkens have not had any contact with each other for hundreds, thousands, possibly even hundreds of thousands of years. The cultural and linguistic differences between the two groups would be fascinating to study. Not to mention the architectural differences, because the underground Irkens would probably carve a space out for themselves in between the rock and the wires completely different from mainstream Irken architecture. And I know you said the undergound Irkens don't like the rats, but that doesn't mean they don't eat them. They're probably a valuable source of protein when the nutrient slurry machine is slow or undergoing repairs.

I wanna be a space sociologist/anthropologist, dangit! (That would be a good career for Dib if he ever gets some more empathy).

Speaking of games/media that remind me of Irken cities, I think a lot about Ruiner. Just, the colors of it. The glowy lighting. The constant advertising. The soundtrack makes me think of the background ambience of Irken cities. Oh, and the constant, brutal violence and exploitation in the gameplay and story of Ruiner. Can't forget that too.

Take out the Earthen cultural references and humans and add some spacebugs, and you've got an off-planet trading city.

That sounds like a secret area in a video game that you can access after getting the special ability.

That could be cool as fuck in a story. Like, a secret hideout that can be accessed through the clawholds that are strategically placed on an old wall to look like it had been damaged over time.