Overview
Oxygen Not Included (ONI) starts you deep in an unfamiliar asteroid, in control of 3 Duplicants. The game advises you to “Start Digging.” But to keep your Duplicants alive and avoid failure, you’ll have to do a lot more than just dig. This guide aims to help new players through the first few cycles.
Select the right duplicates
The correct choice of the first 3 duplicates is very important. Try to select specialists in some field, that is, people who have more than 4.5 points in a given field. Search for a good digger/miner, preferably with high athletics and ideally with high strength, so that he can carry more materials. Digging tunnels and creating new rooms will be your daily bread during the game. The next character should preferably have a high construction skill and, if possible, lots of creativity. The third and most important role for most of the initial stage of the game is a scientist. He must have a high learning statistic. It gives not just a bonus to research, but it also earns more experience in other areas. Later on you can also choose a good cook. However, you will be oscillating around the first three roles. Medicine strengthens the body’s health and tinkering affects the use of machines. It is also used when repairing broken machines and devices.
Afterwards, you should look at the traits, that have an additional effect on your subordinates. Duplicants usually have one positive and one negative trait. Note, that sometimes the character has, e.g. high creativity, but has the “Uncultured” trait, meaning he cannot create paintings, which are an area where he would use his creativity. You can find information about traits in the chapter on duplicants, here is some information that will be useful at the start.
- Recommended; Driver’s Longs (less oxygen consumption), Iron Gut (can eat anything without unpleasant consequences), Germ Resistant (increases overall immunity of the body).
- Avoid; Flatulence (bloating, the duplicate will produce Natural Gas), Mouth Breather (needs twice as much air to breathe), Biohazard (the duplicate is more susceptible to diseases).
- Neutral; Narcoleptic (can sleep at any moment), Pacifist (cannot fight), Yokel (cannot conduct research).
The third section contains information about the decor expectation and Food of a given character. If you have the possibility, try to choose a duplicate that has expectations close to or below zero. The Food Quality expectations are based on duplicant’s experience level. Next to the decor expectation is the last and simultaneously a very important piece of information – stress response.
Once the stress levels of a character reach 100%, your people may react in one of the following ways: they will vomit (Vomiter), cry (Ugly Crier), gorge on food (Binge Eater), or begin smashing your base to pieces (Destructive). It is much better to choose the characters that have the first feature, the vomit is simply contaminated water, which can then be used if you build the base properly. Cry, on the other hand, will affect others, increasing their stress levels. A glutton may become a deadly threat if you have limited food supplies, as he will eat through your reserves, leaving nothing for the others.
To summarize
Try to select specialists in specific fields: a digger, a builder and a scientist. You can shuffle duplicants any number of times. Try to select the skills and traits that suit your needs, and eventually accept the choice if the character has low expectations for the decor and the best, non-aggressive response to stress.
First Steps
Get acquainted with your surroundings. Maps are generated randomly, the same concerns the amount of resources and water. Sometimes you will find many caves with creatures or masses of buried objects around your starting location. At other times you will find abundant algae stocks or plenty of copper ore. It is worthwhile to find out at the very beginning, towards which side to dig and improve the base in order to get the necessary resources.
The first step you want to take is to start digging around to gather materials, increase your space and get access to water and other oxygen pockets. At this early stage you should try to avoid any contaminated water/oxygen, poisonous gases or vacuum spaces. Although these won’t kill your Duplicants (Affectionately known as Dupes), they do complicate life early on. A golden rule of ONI is “Don’t expand too fast too early.” This includes accepting new Duplicants from the Printing Pod, not just making your base bigger! Not only will your Duplicants waste time digging out areas, your small oxygen supply will be spread out over a larger area, hastening your death by low oxygen.
Your first building should be an Outhouse, which you can find in the Plumbing menu. Because the bladders of Duplicants fill up once every cycle (twice if they have the Small Bladder trait) it is important to supply them with a toilet. If not, they’ll make a mess on the floor, which creates Contaminated Water. When a Duplicant steps in contaminated water they will become stressed out. Luckily, contaminated water can easily be mopped up, however Duplicants must step in clean water in order to clean it up.
At this point, you can begin to think about expansion and growing your colony to survive past the first few cycles.
Buildings & Choices
At this point it is recommended to clear a space to make Cots for your Dupes. Having a bed to sleep in decreases Stress and prevents them from getting the Sore Back debuff from sleeping on the floor. You should leave a space or two between every couple Cots for future items you might want to build (e.g., Decor). Leaving a gap between the ceiling and top of any items you build early on can be beneficial for the same reason). That way, later you can clear up this space and add items to increase the Decor, which further lowers stress. But this isn’t important in the first few cycles.
Stress
What will kill most colonies is an overload of Stress. When a Duplicant reaches 100% stress they will exhibit a stress response. This usually makes them incapable of carrying on with their assigned tasks. One stressed dupe can also increase the stress of others with their stress response. For example, a dupe who’s a Vomiter, will of course, vomit when stressed, generating large amounts of Polluted Water. This can contaminate drinking water and spread disease, and other dupes will have to step in it to pass by or clean it up, increasing their stress levels. Left unchecked this can quickly spiral out of control, and your colony can fail quickly. Thus managing stress is one of the most important things for a colony.
Food
One of the other most important concerns is food. Duplicants need a steady supply of calories to keep running around like headless chickens. Duplicants will burn about 1,000 kilocalories (kcal) per day, 1,500 if they have the Bottomless Stomach trait. You start with 20,000 calories worth of rations, but you’ll need to supplement this before long. Usually excavating nearby chambers will provide the colony with Muckroots, Meal Lice, and Bristle Berry.
Food should be your priority for now as your starting rations will only last your 3 Duplicants for a little bit over 6 cycles. You can gather a few wild Muckroot and Meal Lice growing in the air pockets around your base, but they are not a sustainable food source and are only supplemental for now. Next build a Microbe Musher, a Manual Generator, and a Tiny Battery so you can start producing Mush Bars so your colony does not starve. It is also a good idea to build a Wash Basin at the entrance(s) to your food generation/preparation area to avoid contaminating food with Food Poisoning Germs. These are unlikely to be infectious Diseases for the first several cycles, but it’s better to be safe, as illness can be hard to stop after an outbreak starts.
Once you unlock the Planter Box (first item on Food branch of the Research tree), you will be able to grow your own Mealwood plants and make steady supply of Liceloaf with it. While Mealwood’s production of Meal Lice is equally slow in Planter Boxes and Farm Tiles, Farm Tiles take up less vertical space, so you will want to unlock it through the Meal Preparation research fairly quickly.
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Storage
Now you need a place to store all the materials you have gathered by digging around, otherwise your Duplicants will keep running around to get the materials and will gain Stress from messy surroundings. Storage Compactors are easy and cheap to build, so you can build a lot of them. I suggest starting with a maximum of 2. Later on make a room to place all your Compactors, as they create negative Decor and because some materials, such as Polluted Dirt, will produce Polluted Oxygen and carbon dioxide while they are in your Compactors. For your Duplicants to start storing the materials in the Compactors you will need to click on it and choose what they should put in each Compactor.
Water
Water will be required for many things in your colony, including food production, oxygen production, and sanitation. Make your way to the nearest spot of water to allow your Duplicants to collect water and bring it where it’s needed. As of the Outbreak Update, you will need to build a manual Pitcher Pump over your water source to bottle the water to be used or moved. A Bottle Emptier will be needed if you want to move water from one reservoir to another or collect Polluted Water in a safe location for sanitation purposes. Later you will be able to move clean water around with electric pumps to make it 
more convenient for usage. You will also be able to filter contaminated water with the Water Sieve.
Oxygen
Considering the name of the game, Oxygen may sound like the most important resource, but for the first few days, it’s not. The supply you start with and the pockets you connect by digging around will suffice for a while before you need to get into real oxygen production. Your first way to produce oxygen will be the Algae Deoxydizer, which requires Algae and power to work. You should already have a Manual Generator and a Tiny Battery set up by now to power up your Microbe Musher. Simply connect your 
Algae Deoxydizer to it with wires (ideally running them through floors and walls to avoid negative Decor effects). Algae can be found all around the world and sometimes you can hit some very big spots, but they are not renewable and producing oxygen uses a lot of it, so they won’t be your source of Oxygen forever. For now one or two of the Deoxydizers will do the job. The next source of Oxygen to eventually use is the Electrolyzer which converts your large Water reserves into a large amount of Oxygen and a small amount of Hydrogen. Later you will be able to turn Slime into Algae, but the process is very slow and not a super effective way to make Oxygen.
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Research
Now that you have the basics covered, you can start discovering new technologies to keep your colony alive. It can be appealing to start with oxygen production researches but your colony will starve to death before running out of oxygen at this point. Start with the Basic Farming research. This will allow you to place Algae Terrariums to get rid of the Carbon Dioxide produced by digging around. You will also unlock the Planter Box which is very important to start growing Mealwood using the seeds you started with and the ones you can gather by digging up wild Mealwood plants. Place you Planter Boxes as far as possible from the other appliances as they produce heat and this will kill the plants. Power Regulation should be your next research as your Manual Generator and Tiny Battery won’t last very long with all the new components you added.
Final Notes
The first few days of a colony shouldn’t be too stressful. With a supply of Rations, blocks of Oxylite, and easily accessible food, its hard to die early on. But mismanagement early on can make later days much harder, and cause your Colony to go kaput sooner than you’d like. Oxygen Not Included has lot’s of hidden content sprinkled around the map so make sure to explore once you’ve got your base somewhat sustainable. Be careful to avoid Swamp Biomes though as they contain lots of the deadly Slime Lung Germ which can rapidly annihilate your entire colony.
Oxygen is essential for your duplicates. Pay attention to its concentration in places where your people will work. If it starts to run out, they will hold their breath and they will continue working without oxygen for a short time and then they will run to the nearest place with oxygen to replenish its supply. The larger the blue glow in the room, the more oxygen there is. You can also hover over a given field, in order to see how much oxygen there is.
Gas flow. This is a very important factor while building a base. Remember, that oxygen usually rises and carbon dioxide, which is exhaled by your colonists, falls downwards or into the bottom right-hand corner. This means that if you dig down, your people will be more exposed to the lack of oxygen than when digging up. It would also be better to place the bedrooms in the middle or upper part of the base than at the very bottom. Use the oxygen overlay to quickly figure out the situation.
Take care of the food supply by growing crops. Remember that plants require a sufficient amount of air to properly grow. Lack, or even insufficient amount of gases in the environment will halt their growth. Each plant species prefers different temperature ranges, and you need to be aware of them when planting a specific crop. Some of them will require warm environment, some other – a cold one.
Your duplicates can climb up to 1 or 2 fields and jump one field. Remember this when expanding your base. You will be able to receive new people from time to time, which will be indicated by the appropriate information and glow around your starting object – the Printing Pod.
When it comes to digging, watch out for sand tiles, as they can fall as you dig other materials from underneath them. Additionally, your characters can dig up to two tiles away from their position. The same principle applies to pumping water.
Be careful when digging near water tanks. Each mineral has its own resistance to water pressure. If you dig a long tunnel just one tile away from water, the rock can start to burst and water will flood your base. Not only can it drown your colonists (thankfully it does not happen instantly), but it also prevents you from using multiple machines in your base. It will be the most difficult for you to get rid of water at the beginning of the game, when you do not have the proper equipment to remove excess water.
The first object to build is the outhouse! Seriously, you do not want your base flooded by the physiological secretions of your duplicates. Not only does this affect the decor factor, but it also increases the stress level and the generated contaminated water also produces contaminated oxygen. Only drawbacks.
If a duplicate dies at the beginning of the game, bury his body. Otherwise, his corpse will start to spawn creatures, the Morb, which exhale contaminated oxygen. They are not a direct threat but will make your life difficult. At some point, you will be able to use their skills to your advantage. (See section: Base, Special Rooms, Morb “Farm”).
Stress. If a given duplicate reaches 100% in the stress tab, he will start vomit or destroy the environment depending on his behaviour. If he vomits, there will be contaminated water flowing within the base. On the other hand, if he explodes with anger, he will destroy some object or machine in the base, usually the ones most needed, such as the generator or machine needed for the production of oxygen. Take care of the decor of your base and build the appropriate structures, that will reduce stress. Clean air and good food will also have a positive effect on the duplicants.
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Thanks to Oxygen Not Included Wiki, Gamepressure and friends for providing information for this guide.
Special thanks goes to the following people for finding errors and help me correct them:
- PokeMageTech – ProNetNeutrality
————- Video Game History Curator —————————— Video Game History Steam Group ——-
