Best Colony Sim and Base Building Games on Steam

A colony sim is not a city builder. You are not zoning districts or untangling traffic, you are keeping a small group of people alive through a winter, a drought or a hostile alien biosphere, and watching a single bad decision about food storage ripple outward until half the settlement is starving. The genre lives on that gap between the plan you drew and the mess that actually happened. These are the colony and base-building games on Steam that model it best, and every one of them has an achievement list that rewards surviving something you probably should not have.

1

Against the Storm

A roguelite settlement builder where each village lasts a few hours before the storm wipes the map and you carry your upgrades into the next one. It turns the genre's slow decay into a tight, replayable loop, and its 80 achievements push you into biomes and species combinations you would otherwise avoid.

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2

Oxygen Not Included

Klei's brutal asteroid-colony sim, where every system is a physics problem: heat has to go somewhere, gases stratify, and your duplicants will happily suffocate while you debug a pipe. Densest simulation on this list by a distance.

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3

Frostpunk

Part survival colony sim, part moral pressure cooker: you build a city around a single coal generator and then decide what you are willing to do to keep it burning. The 115-achievement list covers most of those decisions and their consequences.

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4

Timberborn

Beaver colonies that survive by damming rivers and hoarding water for the dry season, with genuinely clever verticality and terrain shaping. Gentler than the rest of this list without being shallow.

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5

Going Medieval

A medieval settlement sim with full multi-storey construction, so you can dig cellars, raise keeps and actually defend the thing you built. 94 achievements covering building, defence and survival make it one of the meatier lists here.

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6

Frostpunk 2

The sequel scales up from a single generator to a sprawling city and a council that argues back, so the pressure is political as much as thermal. Its 79 achievements lean hard on run-long restrictions, which makes it the most demanding completion on this list.

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7

Banished

The stark, unforgiving ancestor of the modern wave: no combat, no tech tree gimmicks, just food, firewood, tools and a population that can quietly spiral into a death loop. Still worth playing for how little it forgives.

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8

Stranded: Alien Dawn

A crashed-crew survival colony sim on an alien world, with strong character management and escalating threats from the wildlife. The most approachable entry point if the deeper sims here have bounced off you before.

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9

Prison Architect

A colony sim wearing a very different hat: your settlers are inmates, your logistics problem is contraband, and your failure state is a riot. Short achievement list at 18, but the sandbox runs far longer than that.

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10

Songs of Syx

Ugly on purpose and enormously ambitious, simulating a settlement that grows from a handful of people into a city of tens of thousands with its own economy and unrest. For players who want the spreadsheet underneath showing through.

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Updated 2026-08-28. Every game links to its full SteamVault page with achievement stats, rarity and community completion times.