Improvements such as spaceports and arcologies have no trade-off. In general, there is no advantage to not building them. Most don't even consume resources or work units, so there is no reason to not build them as soon as possible.

And if the player doesn't have an interesting choice to make, then it's not a fun game mechanic. We should either get rid of it (improvements are built automatically) or add enough trade-offs to make the choice interesting.

Below are some proposals for making the choice interesting.

Resource Consumption

Some advanced improvements should consume resources. For example, arcologies should consume trillum and possibly chronimium. Shortages of those resources might cause the arcology to degrade, causing accidents and disasters.

We might also require these resources (in larger quantities) during construction.

Limited Slots

Perhaps worlds can have limits on the number of improvements that can be built. Once the limit is hit, the player must destroy an existing improvement to build a new one. Of course, you would still be able to upgrade improvements (e.g., upgrade from a Subtropolis to an Underground Arcology).

This mechanic only works if there are alternatives. For example, using a Foundation world is an alternative to building a Fusion Program. But improvements like a Spaceport have no alternative (unless you don't want to trade).

New Improvement Types

Adding more types of improvements would introduce more choice for the player. Here are some examples:

  • Civil Defense Program: This improvement makes it harder for an attacker to conquer the world. Perhaps it adds bonuses to infantry (when defending) or perhaps it introduces new units (units that cannot leave the planet).
  • Early Warning Network: This improvement increases the scanning range for the world.
  • Recycling Program: Creates raw materials (e.g., hexacarbide) in proportion to durable goods and luxuries consumption.
  • Solar Constellation: Creates trillum from solar energy.


This is the current list of improvements:


Air Processor -> Domed City -> Sealed Arcology
Flare Shelter -> Shielded Habitat -> Shielded City -> Shielded Arcology
Floating City -> Ocean Arcology -> Planetary Arcology
Hypermetropolis -> Urban Arcology -> Planetary Arcology
Life Support System -> Pressurized Habitat -> Domed City -> Sealed Arcology
Radiation Clinic -> Shielded Habitat -> Shielded City -> Shielded Arcology
Subtropolis -> Underground Arcology -> Planetary Arcology

Fusion Program
Biotech Program
Antimatter Megaprogram (capitals only)
Quantum Megaprogram (capitals only)
Post-Industrial Megaprogram (capitals only)

Armored Constellation
Autocannon Constellation
Battlestation Program
GDM Complex
HEL Cannon Network
Hypersonic Missile Complex
Plasma Tower Network

Habitat structure construction is really tedious, and there is no downside to upgrading. Possibly these structures should upgrade automatically when planetary TL increases?

I like the slots idea.

A spaceport doesn't necessarily need an alternative: If not building a spaceport gives you a free slot, it makes a lot of sense on a planet that's within 100LY of its supply planets anyways, since trade only requires a port on one of the planets in a trading pair.

A recycling program could also generate resources in proportion to units that undergo attrition on the planet. You could build it on yards and heavily defended planets.

There should definitely be a structure whose primary purpose is to improve working conditions, and structures that do not meaningfully increase working conditions or even reduce them.

For your list, the militia base, the two jump beacons, and the two administration structures are also improvements, although they are designationOnly.

gc2 22 Jun 2018:

My reservation with this idea is that it could just end up changing what is optimal without creating choices. For instance, if the extra industry generated by the extra population from an arcology exceeds its maintenance costs, then it's still always beneficial to build, it's just not as strong as before. On the flip side, if an arcology can't pay for its own maintenance costs, then it's never worth it.

george moromisato 25 Jun 2018:

@gc2: This is a great point. One idea is to have competing structures. For example, perhaps there are multiple kinds of arcologies, each concentrating on different optimizations. Some arcologies might increase population; others might increase ground defenses or increase production or reduce the chance of civil wars.

Since you can only build one arcology on a world, you would have to choose.

Another possibility is for arcologies to have some limitation that can only be countered by non-arcology worlds. For example, perhaps raw material worlds (trillum mines, etc.) cannot become arcologies because the population would never allow such dirty industries. But of course, arcologies consume a lot of trillum, so someone has to mine it.

If not every world can be an arcology, then the player has to make a choice.