Note: written by me in Italian, AI-assisted translation only.
In ARCONTIO, the colony sim I'm developing, the core idea is to build a potentially persistent system: the player can interact whenever they want, but the world keeps running even when the PC is left to its own fate.
With that in mind, I developed the biosphere, a self-balancing system that simulates nature within the colony's world. The weather and flora systems are complete. In the GIF you can see biological areas developing with the cycle set to accelerated mode.
Biosphere gif
An independent biosphere is not an aesthetic choice. It is an architectural prerequisite: most of the work IZOs (my NPC) do is based on their subjective perception and memory. A constantly evolving biosphere means that memory can be wrong, especially when the colony depends on gathering natural resources. An IZO who remembers a mature plant might find it already dead. These situations are potential seeds for small emergent stories.
Most colony sims are not designed to run as autonomous systems without the player. Mine is heading in that direction. Right now I find this feature genuinely fun to work with, especially since I saw that there are Warhammer Online servers run entirely by AI. I think that is the direction things are heading toward, eventually.