Oxygen Not included: Beginner's Strategy Guide

Oxygen Not Included drops you deep below the surface of an unfamiliar planet with little guidance. This guide full of tips and strategies is here to help.

Oxygen Not Included (ONI) is the latest game from Klei Entertainment, who have been quite prolific in recent years with great games like Don’t Starve, Mark of the Ninja, and Shank. ONI is a sci-fi colony simulator in which you are tasked with keeping alive a group of duplicants who have mysteriously found themselves deep underground on an unfamiliar planet.

In the game, you must struggle to keep your duplicants alive. However you seek to do this is up to, but you must make sure they have enough food, water, and oxygen (duh). You will also want to make sure that your living quarters stay clean, that stress levels stay low, and that you research technologies and explore the environment to accomplish all of the other tasks.

Frankly, it’s a lot to take in, and that’s why I am here to help out with this Oxygen Not Included guide.

Accepting Duplicants

One of the first things you will do in the game is choosing your duplicants from a set of randomly generated ones. With this first set, you can reroll duplicants to get better ones. As you play the game, you will get the opportunity to recruit a new duplicant every so often. Whenever this happens, you will have three duplicants to choose from.

Stats, Pros, and... Is that Guy a Convict?

Each duplicant will have certain stats, as well as certain pros and cons. Stats are generally straightforward, and a tooltip will appear over any of the pros and cons you need to know about.

Some pros are great. For instance, Diver’s Lungs means that the duplicant uses less oxygen. Conversely, some cons are really bad. Like Mouth Breather, which causes the duplicant to use more oxygen, or Loud Sleeper, which is one of the worst cons because it means duplicants will disturb others.

You also have to be wary about certain cons which mean that a dup is incapable of doing a certain task. You can get a dup who has a high number of points in a skill, like mining, when they are not technically capable of actual mining.

Stress Response

Every duplicant also has a stress response. Currently, vomitter and destructive are the only two stress responses I am aware of. 

The former means duplicants vomit when under great stress, and the latter means they will destroy a piece of equipment. Vomit can be cleaned up and added to the water supply (Currently, vomit actually produces extra water that didn’t previously exist. However, the devs are aware of this, so it could be patched out any day now.). Objects can be repaired when destroyed, but this could prove too costly. All things being equal, I’d choose vomitter because it’s less likely to cause a chain reaction of bad side effects.

Be Patient

If none of the dups available within a given batch seem promising, then you can always choose to not recruit any of them. Instead, wait for the next batch.

Early in the game, you might want to keep your team size between 4 and six dups, because more dups means more used resources; you don’t want to grow faster than you can manage to maintain them.

Jobs and Priority Levels

Jobs and priority levels are important ways to ensure that your team is working efficiently, especially as it increases in size. The Jobs tab, found in the top right corner of the screen, helps you to determine which jobs each dup is and isn’t allowed to participate in. Most duplicants are capable of doing any task, but most of them have particular things at which they are less efficient or more efficient.

Similarly, you can set priority levels for individual tasks. This will ensure that dups get around to doing some of the more important tasks first. Don’t ever forget about these, since you can’t directly tell which dup to do what task. You must rely on these tools to parse out what things need be done.


This is super basic, but really the first and only thing you can do at the outset of your adventure. Digging is very important because it helps you explore, shape your base, and gather materials to build the items you need for survival.


One of the most important pieces of information you need to know is that different gasses have different weights. In particular, carbon dioxide, which dups exhale, is heavier than oxygen and will go downward. This means the lowest part of your base will have the most carbon dioxide because it will all drift there. This also means you generally want to keep objects that produce carbon dioxide, like the outhouse, in a place where the carbon dioxide can move easily down.

Hydrogen is the lightest gas; contaminated oxygen is next, then oxygen, chlorine, and carbon dioxide is the heaviest. Oxygen and contaminated oxygen are the only breathable gasses, although contaminated oxygen will slowly increase your dups’ stress, making them less effective at work. Some have theorized that eventually a harsher penalty will be placed on contaminated oxygen, however.  

On top of that, hydrogen is an extremely important element to harvest, and you'll need to cool to run your hydrogen generators. Check this guide hydrogen cooling tips.  

Oxygen Not Included Amenities

This tip can be boiled down to: don't crap where you sleep. While you will need to eventually set up a food source, water source, and air cleaning system, all of these things should be relatively set from the beginning of the game. The area in which you spawn will have plenty of oxygen, and you will be provided with some food to start out.

Before worrying about any of these things, you will need to create an outhouse, so your dups have somewhere to go to the bathroom.

You will also eventually want to make bedding for your duplicants so that they can get a sound night’s sleep. After a few days of sleeping on the floor, they will start suffering penalties.

Research in ONI

There’s a lot of important things you need to do to survive, but almost none of it can be done until you have actually researched some technologies, so let’s cover that first.

To begin research, you will need a research station. But to power your research station, you will need a power supply: aka the manual generator. So build the manual generator, connect it to your research station, and then get someone running it.

Almost all of the initial-level tech is useful to make, but perhaps the most useful will be the farm tech, which gives you access to the algae terrarium, compost, and planter box. You’ll want to set up a compost near your outhouse so that you can turn the contaminated soil into fertilizer, which can then be used in the planter box.


Early in the game, one of the best ways to help stave off suffocation is to place algae terrariums at the bottom of your base where all of the carbon dioxide collects. Placing them in your “carbon dioxide basement" will produce more oxygen for you which will help secure your long term survivability. Algae terrariums consume algae, water, and carbon dioxide. This means they can become costly since they use 2 limited resources, but they are also one of the more effective ways to remove carbon dioxide. 

This being said, later in your play through, you will most likely want to upgrade to an algae deoxidizer, which uses more algae, but no water, or an electrolyzer, which uses water but no algae. To learn more about using these devices, you can read our Alternative Ways to Get Oxygen guide.

Atmospheric Pressure (or Air Pressure)

Much like the scientific term it represents, atmospheric pressure is, in layman's terms, the amount of gas in a given area. You will need to keep your atmospheric pressure at different levels for different plants to grow. While also maintaining a general air pressure that is livable.

Many of the items that create oxygen also allow you to ensure a certain atmospheric pressure in the vicinity around the object, such as the electrolyzer.


One of the popular early food options is the Mush Bar. To make a Mush Bar, you must make a Microbe Musher and use some water and dirt. Be careful, though: it does have a chance to cause diarrhea. Later, a cooking station can be used to fry two mush bars together, thus ensuring that there won’t be any diarrhea.

Some prefer to forego mush bars entirely by quickly setting up planter boxes and growing plants. Bristle Blossoms, in particular, present an attractive option since they are easier to reuse because they drop seeds.


Ironically, water is not actually used to hydrate your dups. Instead, water is used as another resource to make food, bathroom appliances, etc. Currently, there are not a lot of great ways to get sustainable water, which is obviously a problem. Every map will have at least some water on it. And you can purify polluted water using a water purifier. You can obtain water from snow, steam, geysers, and even vomit. Because of how precious water is and because of how limited it will eventually become, you want to make sure to use water sparingly.

Currently, there are not a lot of great ways to get sustainable water, which is obviously a problem. Every map will have at least some water on it, and you can purify polluted water using a water purifier. You can obtain water from snow, steam, geysers, and even vomit. Because of how precious water is and because of how limited it will eventually become, you want to make sure to use water sparingly.

Stress and Decor

The last big topic to cover is stress. Remember how each duplicant has his own reaction to stress? Well, each dup also has his own stress levels. Stress is sorta' a catch-all for human decency. Is your character sleeping on the ground? Well, now they are stressed. Are they stepping in vomit everywhere they go? Well, that’s stressful too. Is there a dead duplicant in the corner who is totes killing your vibes? Well turns out his corpse is more than just buzzkill; it will also stress out your other dups. 

One of the biggest things that can stress out your dups, however, is crappy decor. In short, you want to make the place in which they live seem like home. Add paintings, real floors, lighting, vases, etc. Most of the heavy machinery in the game will reduce decor levels, which is why you must add in decor to counteract this.

Arm Yourself with Your Wit!

Above all else, be witty. As you learn and become a more battle-hardened survivalist, then you can really start experimenting with ONI. There are a lot of beginner tips that you will read -- and that you should abide by at first -- that are not always going to hold true as you get larger, more advanced bases or as you experiment. As the game is continually updated, changed, and given new content, different strategies will become obsolete or viable. 

Stay tuned to GameSkinny for more Oxygen Not Included guides, tips, and strategies. 

Featured Contributor

Graduated from Full-Sail with a BS in Game Design (Speaking of BS, how about that student loan debt, eh?).

Published Jun. 24th 2017

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