Oxygen Not Included Codexery

First Steps

Three colonists, one cramped pocket of rock, and the first breath of a new world.

First Steps is the opening mission of Oxygen Not Included, serving as both the player's introduction to the game's core survival loop and the narrative starting point for the colony. It drops a small crew into a cramped, resource-poor pocket of an alien underground and tasks them with keeping everyone alive long enough to establish a foothold. Every mechanic the player will rely on for the rest of the campaign—oxygen generation, water recycling, food production, and basic mining—is introduced here in a forgiving, guided context.

Because it is the very first thing a new player encounters, First Steps functions as the tonal and mechanical thesis of the entire game: a tiny group of people in a hostile, sealed environment must cooperate with the physics of their world or perish. The mission's deliberately tight space and limited starting inventory make every decision feel consequential, setting the stage for the sprawling colony-management challenges that follow.

Type
Main campaign mission (Mission 1)
Position
First mission in the default campaign
Difficulty
Introductory / Tutorial
Starting crew
3 colonists
Primary focus
Basic survival: oxygen, water, food, and initial resource gathering
Prerequisites
None (campaign entry point)

Lore & Background

The colony ship that carried the crew to this alien world did not land in a welcoming valley. Instead, the vessel settled into a shallow depression in the planet's crust, and the escape pod that carried the first group of survivors deposited them into a narrow, partially enclosed cavern. The air outside is thin and the temperature swings are brutal, so the crew's immediate priority is sealing their small habitat and generating enough breathable oxygen to keep three people alive while they assess their situation.

The rock surrounding them is rich in the raw materials they will need—ore veins, water pockets, and pockets of combustible gas—but none of it is accessible without tools, and their starting equipment is barely enough to scrape by. The mission's narrative weight lies in that tension: they are not explorers with a full kit; they are survivors with a toolbox and a prayer. Every barrel of oxygen they produce, every drop of water they filter, and every meal they cook is a small act of defiance against the void pressing in from every side.

For the player, First Steps is where the abstract promise of the game becomes tangible. The first time a colonist coughs from low oxygen, the first time a water tank runs dry and someone's health bar starts to bleed, the first time a mined rock reveals a vein of copper that will become the foundation of a power grid—these moments land with a weight that later, more complex missions never quite replicate. It is the mission that teaches the player to think in systems before they think in solutions.

In Their Own Story

The hatch sealed with a pneumatic hiss, and Mara pressed her palm flat against the cold metal as if she could feel the planet's heartbeat through it. Three of them. Three names on the manifest, three bodies breathing the same thin air in a space barely wide enough to stretch out in. Kofi was already at the wall, running his fingers over the exposed rock, muttering about load-bearing. Yuki had the oxygen scrubber kit open on the floor, components scattered like a surgeon's instruments, and she hadn't looked up since they'd landed.

"We have maybe four hours before the O2 drops below comfortable," Kofi said. Not a question. A fact, delivered with the flat calm of someone who had done the math twice already.

Mara nodded. She pulled the small mining tool from her belt, tested the charge, and set it against the nearest vein of grey rock. The first strike sent a shower of dust into the stale air. The second revealed a seam of pale blue ore beneath. She exhaled—slowly, deliberately, rationing the breath the way Yuki had taught her in the ship's sim bay, years ago, in a life that felt like a different planet.

Outside, the dark pressed against the single porthole. No stars. No wind. Just the slow, patient weight of an entire world waiting to be carved open, one careful strike at a time.

Reader's Guide

Starting conditions: The crew of three colonists is deposited into a small, partially enclosed underground pocket. They have basic tools, a limited supply of food and water, and a small amount of starting ore. The surrounding terrain contains accessible veins of rock, water, and gas, but the space is tight and the initial O2 supply is finite.

Primary objective: Keep all three colonists alive while gathering enough resources and completing the required survival tasks to unlock the next mission. This typically involves producing a set amount of oxygen, collecting water, cooking food, and mining a minimum quantity of raw materials.

Key triggered events: As the starting oxygen supply depletes, colonists will begin to show stress and health penalties if O2 levels fall too low. Water and food stocks will also dwindle, forcing the player to set up basic production chains (e.g., a water filter, a food source, an oxygen generator). The cramped starting area will eventually feel insufficient, prompting the player to break through surrounding rock to expand.

Win condition: All required resource and survival objectives are met, and the mission is marked complete, unlocking the next campaign mission. Lose condition: All three colonists die from suffocation, starvation, dehydration, or other neglect. The player can pause and replan at any point, so the mission is forgiving for first-time players.

Did You Know?

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