JUSTPLAYBETTER

Oxygen Not Included

A space-colony survival sim where the only enemy is physics. Dig out an asteroid and keep your duplicants breathing, fed, and cool as gas, heat, and germs work against you. No combat, just a chain of systems crises you solve in order.

Progression at a glance

# Crisis When The fix
1 Initial oxygen Cycle 1 to 5 Starting Oxylite runs out. Build an Oxygen Diffuser (burns algae) or Algae Terrarium.
2 CO2 buildup Cycle 3 to 15 Dupes exhale heavy CO2 that sinks to the floor. Let it pool in a carbon pit, add Deodorizers or oxyferns, later a Carbon Skimmer.
3 Running out of food Cycle 5 to 20 Starting rations deplete. Each dupe needs 1000 kcal per cycle. Plant Mealwood and run a Microbe Musher, then farm and ranch.
4 First stress crisis Cycle 10 to 30 Bad decor, food, sleep, and low oxygen stack. Add beds, latrines with wash basins, decor, and a Massage Table.
5 Water and plumbing Cycle 10 to 40 Outhouses fill and you need clean water. Build liquid pumps, pipes, and a Water Sieve, and secure a source.
6 Oxygen scaling Cycle 20 to 40 Diffusers burn finite algae at a poor ratio. Transition to an electrolyzer-based SPOM.
7 Power scaling Cycle 15 to 60 Manual generators cannot keep up. Move to Coal, then Natural Gas, Hydrogen, or Petroleum Generators.
8 Heat buildup (the wall) Cycle 80 to 120 Sealed-base heat has nowhere to go. Insulate, use Wheezeworts, then build Thermo Aquatuner plus Steam Turbine cooling.
9 Disease and Slimelung Cycle 50 to 120 Digging Slime off-gasses infected Polluted Oxygen. Use Atmo Suits, Deodorizers, and Chlorine rooms, or wait it out.
10 Petroleum and deep resources Cycle 100 to 150 plus You need Plastic, Petroleum, and Steel. Run Oil Wells or refineries and Petroleum Generators. The Oily biome is hot.
11 Space progression Cycle 150 plus Reach the surface, defend against meteors, launch rockets. Spaced Out! turns this into multi-planetoid logistics.

The live game runs on the March 2026 stable build. The newest content, the Aquatic Planet Pack, is in public testing (build 731233) alongside the Spaced Out!, Frosty, Bionic, and Prehistoric packs.

Top tips

  1. First three priorities every game: toilets with wash basins, food (Mealwood plus a Musher), and oxygen. Solve those before anything else.
  2. Set up latrines with wash basins immediately, so Food Poisoning does not spread to your kitchen and water.
  3. Do not over-print duplicants. Around 8 to 10 in the early game is plenty, and every dupe adds oxygen, food, water, and stress load.
  4. Isolate and clean Polluted Water and Polluted Oxygen. Keep toilet output away from food and drinking water.
  5. Learn the pipe and bridge rules early. Overlapping pipes and wrong bridge direction are the top cause of base flooding.
  6. Match morale to expectations, especially after training skills. Each learned skill raises a dupe morale demand.
  7. Insulate early and plan cooling before the mid-game heat wall. Generators and electrolyzers heat a sealed base until crops die and machines break.
  8. Do not dig into Slime unprotected. The Marsh biome releases Slimelung, so bring Deodorizers or Atmo Suits.
  9. Respect wire wattage limits and use batteries and transformers so circuits do not overload and burn.
  10. For a gentle first run, pick No Sweat difficulty on the Terra asteroid, or Rime if heat scares you.

Guides

setups

  • SPOM (Self-Powered Oxygen Machine) quick

    The electrolyzer oxygen build that powers itself. Purpose, inputs, and outputs for the machine that ends the algae crisis and carries a colony indefinitely.

  • Cooling Loops quick

    The Thermo Aquatuner plus Steam Turbine loop that genuinely deletes heat and recovers part of it as power. Inputs, outputs, and coolant choices.

  • Food and Ranching quick

    The food chains and critter ranches that feed a colony. From Mealwood and a Musher through farm tiles to Hatch, Drecko, and Pip setups.

progression

  • Crisis Order Cheatsheet quick

    The whole colony on one page. The survival crises in the order they hit, and the fix for each: breathe, eat, destress, plumb, power, cool, then space.

systems

  • Heat Management deep

    The mid-game heat wall, why it filters players, and how to manage it. Insulation, passive sinks, and the Thermo Aquatuner plus Steam Turbine loop.

  • Power deep

    Power generation from manual wheels to petroleum, the transition off coal, and the wire, battery, and transformer rules that stop your circuits from burning.

  • Plumbing and Gas deep

    Liquid and gas piping, the packet model, bridges and valves, and the atmosphere management that keeps oxygen breathable and hazards contained.