There’s a mini-setting in the back of GURPS Bio-Tech about the colonization of a far-off star system, which naturally includes terraforming to suit human needs. In addition to the exploration and settlement aspects, there’s also the part about decision-making. There isn’t a set plan for what to do at Sigma Draconis, as the fleet wasn’t sure what to expect when they arrived.
I can envision a multi-tier game where play happens on several levels. On the highest, players take the roles of the policymakers. They’re heads of the different factions and professional organizations involved in the great endeavor. This is about building alliances and trading favors. The next level down are the explorers. It’s more action-oriented: flying shuttles, exploring terrain, dealing with environmental issues, maybe even finding the remains of alien civilizations, if not living aliens. Finally, there’s the nitty gritty of terraforming and establishing habitations in orbit and on the land.
The levels of play roughly analogize to those in Ars Magica. Magi, companion and grog correlate to policymakers, explorers and settlers in terms of the view of the project: the mile high perspective, a bit closer at a half mile, and then ground level. The trick about this idea — and what originally stumped me about the idea when I read it in GURPS Bio-Tech — is how do you keep each level of play fresh and interesting? I mean, terraforming is terraforming. You can’t really dramatize that.
Although, I did just think of a set-up where a saboteur strikes a remote atmospheric modification station. Adverse weather conditions means everyone’s trapped on the station for the time being, so it becomes a tense situation as everyone suspects everyone else of being part of the so-far mythical fifth column, rumors of which dogged the fleet ever since everyone climbed out of cryosleep.