Oxygen Not Included is Klei Entertainment's colony survival sim where you manage a group of Duplicants trapped inside a procedurally generated asteroid. Every breath of oxygen, calorie of food, and degree of temperature must be meticulously managed through complex piping, ventilation, and power systems. The Spaced Out! DLC adds multi-asteroid colonies and interplanetary rocket logistics. With hundreds of hours of depth in thermodynamics, gas physics, and liquid mechanics, ONI rewards systems-thinking players who enjoy solving cascading engineering puzzles.
Picking the right build determines how your experience plays out. These builds are ranked by overall effectiveness — factoring in damage, survivability, gear requirements, and how well they scale into endgame.
Quick Rankings
| Build | Tier | Playstyle | Core Gear |
|---|---|---|---|
| Researcher | S | Parks at research stations full-time, occasionally operating telescopes for space data. | Super Computer, Virtual Planetarium, Data Banks, Telescope |
| Farmer | A | Tends crops, harvests, and delivers food ingredients to the kitchen. | Farm Tiles, Hydroponic Tiles, Fertilizer Synthesizer, Cooking Station |
| Miner | A | Digs out new areas, clears debris, and accesses buried resources. | Exosuit, Atmo Suit Checkpoint, Dig errands priority |
| Cook | B | Prepares meals at cooking stations, manages food storage and spice production. | Gas Range, Electric Grill, Spice Grinder, Refrigerator |
| Suit Wearer | S | Works in any hazardous environment while consuming suit oxygen supply. | Atmo Suit, Jet Suit, Atmo Suit Dock, Jet Suit Dock |
S-Tier: Researcher
Researchers are essential early game and remain valuable throughout. A high-Science Dupe stationed at a Super Computer tears through the tech tree, unlocking critical systems like Insulated Tiles and Smart Batteries before cycle 50. Late game, they operate Telescopes and Virtual Planetariums for space research.
Core Setup
| Slot | Choice | Why |
|---|---|---|
| Primary Equipment | Electrolyzer | The Electrolyzer splits Water into Oxygen and Hydrogen at 1kg/s water input. |
| Core Gear | Super Computer, Virtual Planetarium, Data Banks, Telescope | Maximizes build potential |
| Stat Priority | Science, Learning | Optimal scaling |
| Key Mechanic | gas management | Gases in ONI have realistic density — oxygen sinks below hydrogen, carbon dioxide pools at the bottom, and chlorine settles above CO2. |
How to Play Researcher
Parks at research stations full-time, occasionally operating telescopes for space data.
Researchers are essential early game and remain valuable throughout. A high-Science Dupe stationed at a Super Computer tears through the tech tree, unlocking critical systems like Insulated Tiles and Smart Batteries before cycle 50. Late game, they operate Telescopes and Virtual Planetariums for space research.
What makes this build work: The synergy between Electrolyzer and gas management creates a gameplay loop that outperforms other options. Core gear like Super Computer, Virtual Planetarium, Data Banks, Telescope amplifies this further.
Pros:
- Highest overall performance
- Clear stat priority (Science, Learning) makes gearing straightforward
- Works in all content types
Cons:
- Popular pick, resources may be contested
- Needs specific gear to reach full potential
A-Tier: Farmer
Farmers handle all food production from Mealwood farms to Bristle Blossom hydroponic setups. High Agriculture skill increases crop tending speed and prevents withering. Late game, they manage Grubfruit and Nosh Bean farms for +8 morale food recipes.
Core Setup
| Slot | Choice | Why |
|---|---|---|
| Primary Equipment | SPOM System | The Self-Powered Oxygen Module combines an Electrolyzer, Hydrogen Generator, Gas Pump, and Gas Filter in a self-sustaining loop. |
| Core Gear | Farm Tiles, Hydroponic Tiles, Fertilizer Synthesizer, Cooking Station | Maximizes build potential |
| Stat Priority | Agriculture, Creativity | Optimal scaling |
| Key Mechanic | pipe systems | Liquid and gas pipes form the circulatory system of your base, carrying water, polluted water, petroleum, and various gases. |
How to Play Farmer
Tends crops, harvests, and delivers food ingredients to the kitchen.
Farmers handle all food production from Mealwood farms to Bristle Blossom hydroponic setups. High Agriculture skill increases crop tending speed and prevents withering. Late game, they manage Grubfruit and Nosh Bean farms for +8 morale food recipes.
What makes this build work: The synergy between SPOM System and pipe systems creates a gameplay loop that offers reliable performance. Core gear like Farm Tiles, Hydroponic Tiles, Fertilizer Synthesizer, Cooking Station amplifies this further.
Pros:
- Most versatile option
- Clear stat priority (Agriculture, Creativity) makes gearing straightforward
- Works in all content types
Cons:
- Lower peak damage than S-tier
- Needs specific gear to reach full potential
A-Tier: Miner
Miners with high Excavation skill dig faster and access Hard Digging for Abyssalite and Obsidian. They're your primary base expanders and resource gatherers. Pairing a Miner with Exosuit training lets them safely excavate in hostile biomes without breathing hazards.
Core Setup
| Slot | Choice | Why |
|---|---|---|
| Primary Equipment | Steam Turbine | The Steam Turbine converts steam above 125C into power and 95C water output. |
| Core Gear | Exosuit, Atmo Suit Checkpoint, Dig errands priority | Maximizes build potential |
| Stat Priority | Excavation, Athletics, Strength | Optimal scaling |
| Key Mechanic | duplicant skills | Each Duplicant has innate attributes (Athletics, Strength, Creativity, Science, etc. |
How to Play Miner
Digs out new areas, clears debris, and accesses buried resources.
Miners with high Excavation skill dig faster and access Hard Digging for Abyssalite and Obsidian. They're your primary base expanders and resource gatherers. Pairing a Miner with Exosuit training lets them safely excavate in hostile biomes without breathing hazards.
What makes this build work: The synergy between Steam Turbine and duplicant skills creates a gameplay loop that offers reliable performance. Core gear like Exosuit, Atmo Suit Checkpoint, Dig errands priority amplifies this further.
Pros:
- Best survivability
- Clear stat priority (Excavation, Athletics, Strength) makes gearing straightforward
- Works in all content types
Cons:
- Slower clear speeds
- Needs specific gear to reach full potential
B-Tier: Cook
Cooks operate the Electric Grill and Gas Range to produce high-morale meals like Frost Burger (+6) and Berry Sludge. While important for morale, you only need one dedicated Cook since meal prep is fast. Cuisine skill level determines which recipes are available.
Core Setup
| Slot | Choice | Why |
|---|---|---|
| Primary Equipment | Aquatuner | The Aquatuner cools any liquid passing through it by exactly 14C per pass, outputting the heat into its surrounding environment. |
| Core Gear | Gas Range, Electric Grill, Spice Grinder, Refrigerator | Maximizes build potential |
| Stat Priority | Cuisine, Creativity | Optimal scaling |
| Key Mechanic | research tree | Research progresses through tiers using Research Stations (tier 1-2), Super Computers (tier 3), and eventually Interplanetary Research for space-age tech. |
How to Play Cook
Prepares meals at cooking stations, manages food storage and spice production.
Cooks operate the Electric Grill and Gas Range to produce high-morale meals like Frost Burger (+6) and Berry Sludge. While important for morale, you only need one dedicated Cook since meal prep is fast. Cuisine skill level determines which recipes are available.
What makes this build work: The synergy between Aquatuner and research tree creates a gameplay loop that provides a unique approach. Core gear like Gas Range, Electric Grill, Spice Grinder, Refrigerator amplifies this further.
Pros:
- Strong in group/team content
- Clear stat priority (Cuisine, Creativity) makes gearing straightforward
- Excels in its niche
Cons:
- Weaker solo performance
- Requires deep game knowledge
S-Tier: Suit Wearer
Not a traditional class but a critical role — any Dupe with Exosuit Training can work in hazardous areas without oxygen concerns. Suited Dupes ignore gas environments, allowing them to work in chlorine-filled areas, vacuum, or scalding hot biomes. Every late-game Dupe should have this skill.
Core Setup
| Slot | Choice | Why |
|---|---|---|
| Primary Equipment | Solar Panels | Solar Panels generate up to 380W each when exposed to direct sunlight on the asteroid surface. |
| Core Gear | Atmo Suit, Jet Suit, Atmo Suit Dock, Jet Suit Dock | Maximizes build potential |
| Stat Priority | Athletics (suits slow movement), Strength | Optimal scaling |
| Key Mechanic | space exploration | Space exploration requires building rockets from modular components — nosecone, fuel tank, engine, cargo bay, and habitat modules. |
How to Play Suit Wearer
Works in any hazardous environment while consuming suit oxygen supply.
Not a traditional class but a critical role — any Dupe with Exosuit Training can work in hazardous areas without oxygen concerns. Suited Dupes ignore gas environments, allowing them to work in chlorine-filled areas, vacuum, or scalding hot biomes. Every late-game Dupe should have this skill.
What makes this build work: The synergy between Solar Panels and space exploration creates a gameplay loop that provides a unique approach. Core gear like Atmo Suit, Jet Suit, Atmo Suit Dock, Jet Suit Dock amplifies this further.
Pros:
- Unique, rewarding playstyle
- Clear stat priority (Athletics (suits slow movement), Strength) makes gearing straightforward
- Excels in its niche
Cons:
- High skill floor, punishing when misplayed
- Requires deep game knowledge
Build Progression Path
- Start with Farmer — the most forgiving option for learning the game
- Transition to Researcher once you understand core mechanics and have access to Electrolyzer
- Keep a Miner setup for content that keeps killing you
- Try Suit Wearer for a fresh experience once you've mastered the basics
Gearing Tips
- Invest in your primary equipment first — it gives the biggest power spike
- Build a SPOM (Self-Powered Oxygen Module) by cycle 30 — one Electrolyzer, two Gas Pumps, a Gas Filter, and a Hydrogen Generator in a sealed room provides oxygen for 8 Dupes with zero external power.
- Insulate your base perimeter with Insulated Tiles made from Igneous Rock (not Sandstone) to prevent heat bleed from hot biomes — temperature creep is the silent colony killer.
- Don't spread upgrade resources across multiple builds until endgame
See our tier list for current meta rankings, or the beginner's guide if you're just getting started.
