One of the ideas I've had is to split the gameplay up into distinct stages that increase in complexity from managing one colony on a planet to managing multiple colonies, then a solar system, and then multiple solar systems. Each stage would have its own challenges and goals, which when met lead logically to the next stage. The gameplay of previous stages isn't removed in later stages, for example when you're exploring the galaxy you can still build colonies on the individual level on planets. The purpose of the stages is to gradually introduce the player to the game mechanics.
In successive stages, the gameplay of previous stages may be packaged up and made simpler to execute to prevent the need to micromanage. For example, once you're colonising other worlds it might be a good idea to let the player construct templates for colonies that will automatically build and then tell him when they're done. The player still designed the template so the game isn't playing itself but a lot of the micromanagement is replaced by player-directed automation.
Stage 1:The game would start with your colony ship having crashed on an unknown planet. Players will have to explore the surrounding area for resources and construct a sustainable colony. You only have a certain number of people in stasis, who are revived once your colony supports them. This allows rapid "population growth" over a relatively short time-scale but puts hard limits on how much progress can be made in stage 1. The player has to explore in order to find parts of the crashed ship that can be reverse-engineered into structures like water extractors and solar power plants.
The ultimate technology in stage 1 is an orbital satellite, which requires parts to be found near the crash site and significant research and industry to put together and launch. This acts as a gating mechanism, making sure the player has thoroughly explored his immediate vicinity and making sure your colony is producing enough research and industry for stage 2. Once launched, the game proceeds to stage 2.
Starts with: Colony ship crash on planet.
Goals: Build a functional colony. Research technologies to adapt to new environment. Explore area around crash site.
Ends with: Research and deploy satellite.
Stage 2:Stage 2 seamlessly zooms the map out to a full planetary view. The Satellite scans the planet for additional ships lost in the crash. One will be in a normal terran environment zone, but the others will be in desert, ice and underwater areas. The goal of Stage 2 is to develop the technologies required to inhabit these environments successfully. The satelite also finds resource wells within a certain radius of any colony. These are areas of land on which the player will get a bonus to a particular activity like mining, research or energy generation.
Once a fully sustained colony is opened in any of the locations and enough people are revived, they can start extracting major components of their crashed ship. Each crashed ship contains a working part of a hyperdrive, and once every colony is up and running and has extracted its part of the hyperdrive, the player can research to rebuild a new hyperdrive. Stage 2 ends when the player has built probes with hyperdrives able to survey the solar system.
Starts with: Satellite launch.
Goals: Scan for other ships lost in the crash, set up colonies on each of them, extract hyperdrive.
Ends with: Build interplanetary probes.
Stage 3:Stage 3 is all about exploring the solar system and researching ship and space technologies. The solar system is divided into a two-dimensional plane of sectors, and the player can build and send probes to a particular sector to scout for objects. Ground-based observatories discover planets and moons, while probes can find much smaller objects. Bigger telescopes can be researched and built, with the ultimate telescope being an orbital space telescope. This can be used to periodically probe a sector of space from a distance much faster than sending a probe.
Orbital probes can be sent to planets, which scan the planet for anything interesting and then send the data back. A planetary rover can be dispatched to the site of any interesting finds to make a discovery, which then unlocks new technology. The goal is to research outpost and colony technology, so you can set up mining outposts on asteroid fields and colonies on Desert/Ice/Ocean planets. The ultimate goal is to find an ancient ship on one of the planets with an FTL drive, and set up a colony to extract it. The drive is powered by a rare element, which you have to find and mine a sufficient quantity of before making FTL-capable ships.
This acts as a gating mechanism for stage 4, ensuring the player has researched and figured out how to use probes, has built a space telescope, has a colony on at least one other planet and has at least one mining outpost on a planet, moon or asteroid field. Once FTL-capable ships are built and a space telescope is operational, the game moves to stage 5.
Starts with: Launch probes with hyperdrives.
Goals: Explore solar system, send probes/rovers to planets, research ship and space techs, discover ancient ship, reverse-engineer FTL drive.
Ends with: Produce FTL-capable ships.
Stage 4:Explore the galaxy. This is the main competitive game, with stages 1-3 really acting as a steady introduction to the game's micromanageable elements. I'd like to offer the option to skip straight into stage 5 galactic warfare, but at the same time I want it to be desirable to play through stages 1-3 in a new game. I'll probably achieve this by giving some kind of big benefit for completing or performing well in each stage that's carried on to the next stage. Perhaps exclusive technologies that can be found in each stage, or special homeworld-only buildings that can't be built after stage 4. People familiar with stages 1-3 should also be able to quickly burn through them to get to stage 5.
Stage 5 will involve colonising the galaxy, making contact with other civilisations, diplomacy, researching bigass ships and guns and smashing the crap out of the other races. Typical 4X gameplay, MOO2 style. More details to come as I develop the ideas.
Starts with: Build FTL drive capable ships.
Goals: Explore galaxy.
Ends with: Kill all the dudes.