Cities are a natural setting in a science fantasy universe. Built over their own ruins, where the past and future mix into a heady kaleidoscope of people and technology. Cities are a microcosm of the world around them, but also with unique details and inertias. Without having to write (or read) tons of lore, just what kinds of buildings are in a city, what people do there, how it engages with the surrounding environment says a lot.
The upside of a modern or medieval theme is it's very easy to communicate what function individual elements of the game serve. For example compare “stone” to something invented like “plastoid”. Everyone knows what stone is, how to get it, and its benefits and downsides. “Plastoid” needs an explanation, and requires more from the game on what it is, what it does, and how to get it.
For a space fantasy setting like Amberspire's, the details are important, and the resources are the most important. Them and the buildings are the first elements of the theme and game the player interacts with, and continues to throughout. What they are, do, and how the player gets them reflects the setting of the city and the world, and is a direct line to the player's mind on what's going on in this world.
That said, communication is still a concern! For Amberspire I’ve tried to mitigate this issue. The first is to use only common words like Metal, Quartz, or Sunlight. A few might bend this rule slightly (they don't have final names as of yet!) but they will be understandable within the broader language of sci fi concepts.
The next big thing is being very loose with the idea of what constitutes a resource. Resources like Shadow, Ritual, or Glow represent ephemeral and abstract concepts but are still treated as other resources: created by buildings and used to make your city function. The game slowly introduces these resources and the player can begin to interpret what they are by how the city uses them. These are in place of fussy, complex, or interchangeable sci-fi/fantasy resources that can fall flat. I don’t expect the player to know what Horizon, Tides, or Gathering are when they start the game, but they do represent things and interpreting what they are is an aspect of the game.
The resources are a primary method of communicating science fantasy to the player, as important as the art and music. If the player is thinking in terms of wood, sheep, or stone, no matter what the aesthetics are telling them, the theme is undercut by how the player thinks about the game in a straight mechanical sense. When playing Amberspire, sentences like
I need the Lighthouse to produce Void to construct a Clockworks.
I'm not sure whether the Silk is better used at the Starport or the Arena.
A nearby Observatory can generate Starlight for both a Necropolis and Arboretum.
will cross the player’s mind. And that brings forth the science fantasy theme that I want, in a way that's inescapable.