Explore the Colony, Not the Planet. You should absolutely consider taking the action outside the colony domes. Mars is significantly smaller than Earth, but it’s still an entire planet. There are ice caps, mountains, and canyons. The list of Colony Health Markers provides at least one option, “Others,” that allows for the possibility of alien lifeforms. If you were so inclined, there is an entire game’s worth of material outside the domes. And if your genre preferences tend towards exploration and the tropes of the John Carter series, Mars provides. But — you really shouldn’t overdo it on this type of action.
Mars Colony, for all its trappings and technology is not a sci-fi survival game, and it’s not an action-adventure game. The title is purposeful, and it guides you towards the happenings inside the dome even if the lives of those living outside the dome affect those within. Most people on Mars, by far, live under the colony domes. Keep the action focused on those people, and keep the larger planet as a symbol of Mars’s potential. It is an expanse of barren, ochre rocks, but it’s the only home known to many of the inhabitants in the colony. Celebrate the planet’s beauty, but do so through the perspective of politics and struggle.
Nonetheless, when you do venture outside the colony dome (if you do), there are a few ways to make your excursions punchy and memorable. First, you might bring the outsiders in. There are plenty of tiny outposts and loners doing work for the colony out there in the cold. If the political policies of the colony interfere with their way of life, they are likely to venture inside and make their voices heard. Second, you might treat some of the outposts as extensions of the colony to be toured by Kelly in the same way she might visit any other part of the colony. The difference, of course, is that her safety is at great risk when away from the protocols and relative security of the dome. If you want a dose of action in your game, feel free — but reserve it as a moment of intensity that stands out over the course of the entire story. Finally, you can always bring the environment of Mars inside the colony. A breach in the dome is potentially catastrophic. Maybe the colony needs to get in touch with its pioneering, rough and tumble origins to finally come together. There are many options, but my overarching advice is to find a way to keep the confict centered on human interaction even when the Martian desert asserts its dominance.