I don’t think most players would be interested in always being forced to become cavedwellers just because their computers aren’t so good…
Huh. My understanding from the dev forums was for the smallest Planet in Planet generation to be Moon-sized. Unless that idea has changed.
What about literal moons? Let the gas giant you orbit protect you instead of using your own magnetosphere and let the tidal effects prolong the time you have with active plate tectonics. You’d likely need an immense source of new gasses to stay habitable, as only a single moon in our solar system has an atmosphere, but it isn’t impossible.
Through it’s probably no more common than regular earthlike planets being, well, planets.
Terra Firma - Complete a Playthrough on a Standard World Planet Setting.
Lands lost to water: Being a species endemic to a continent, see it reduced to a small-ish island.
Is that Atlantis? - Have previously sunken land re-appear due to dropping ocean levels, either from an Ice Age, or because they are boiling off due to extreme heat from runaway greenhouse effect.
Mission Failed Successfully: Turn a mars-like planet into a venus-like planet because the ones responsible didn’t stop increasing the greenhouse effect
At least it isn’t boiling anymore! - Accidentally turn a Venus-like planet into a Mars-like planet because the people in charge of terraforming got rid off too much atmosphere.
Please do not resist: Try “liberating” a country (with malicious intent)
“I wouldn’t say freed, more like, under new management” - Tighten, Megamind (2010).
Soon enough to be integrated into the strangely behaving civ…
Gliese 581c - Complete a Playthrough in a Large World Planet Setting.
Mars: Complete a Playthrough in a Small World Planet Setting.
Dangerous Oligarchs Grab Everything - Make your government run by billionaires who decide to slowly cut funding for everything.
M.A.D.: Teach your populace the bad results of a nuclear war
Pacifism - Teach your population the bad results of any war, and make them against waging violence, unless it is for self-defense as a very last resort.
Tower of power: Have your culture view towers as centres of (political) power.
Tower of Babel - Attempt to make the tallest tower in your world and proclaim yourself as a god, but the tower falls down because of overlooked engineering problems.
Eden: Originate as a sapient species from a peaceful-garden-like location