History YMMV / OxygenNotIncluded

*** Deeper Diver's Lungs is even better, being Diver's Lung on steroids, although balanced out by the fact that it can only be randomly acquired through nuromachines. A duplicant can have ''both'' traits because of this though, which makes it so they basically making it so they don't even really take a fraction out of the oxygen they breathe.
** Sunny Disposition removes 20% stress per cycle, making morale requirements pretty much irrelevant for that dupe.

** Shinebugs have a very useful property: due to being quick breeders, they don't need food to produce an egg before dying while tame, even if left unfed. By breeding a bunch of them and cramming them into a room with solar panels, you create a "Shinebug reactor". This structure, for a grand total of zero upkeep and zero heat, can produce decent amounts of constant power, enough radiation to quickly feed a radiation collector, and as a bonus it will advance you through the Shinebug mutation chain.
* FridgeBrilliance: Floral Scent is treated as a germ that only dupes with "Allergies" are susceptable to. This is basically how allergies work. The immune system treats something harmless as a disease agent and makes you miserable.

** Thanks to the addition of Buddy Buds and floral scent "germs", Morbs have become the go-to way to produce Oxygen. Because of the way the game is programmed, no two sets of germs can occupy the same tile. By filling up a room full of Buddy Buds and then using uncleaned outhouses in said rooms to spawn a bunch of Morbs, as well as some deodorizers to clean up the [=CO2=] as it leaves the room, you now have a completely near 100% maintenance-free way to produce a bunch of oxygen without worry of slime lung pollution.

* ThatOneDisadvantage: Negative traits range from completely inconsequential to "never ever pick this dupe unless you're on a self-imposed challenge". In particular, Flatulent dupes generate small amounts of natural gas periodically, not enough to be useful for energy generation, but enough to screw with your plants, Narcoleptics drop anything they carry when they randomly fall asleep, Mouth Breathers and Bottomless Stomachs simply chew through two dupes' worth of resources, and those with Allergies will get '''extremely''' pissed off when exposed to Floral Scents (which pop up among certain common plants and brighten non-allergic dupes' days), practically guaranteeing they peak stress in a matter of seconds.
* ThatOneLevel: Swamp biomes were this at one point, before changes to disease mechanics rendered the near-ubiquitous Slimelung infection found in dirty swamp Slime and polluted water to be irritating rather than highly deadly. In the modern incarnation of the game, the closest equivalent is probably extremely hot biomes like the Oil or Volcanic Biome; while the Abyssalite deposits that streak the map keep the heat confined early on, once that protective layer is breached the seeping heat can easily cook a base if the player isn't quite familiar with heat management mechanics

* LowTierLetdown: Among the geysers, the only one that's largely seen as more of a hinderance than anything else is the chlorine geyser. Chlorine only has one very specific use; killing germs. Which is easy enough to set up a chlorine cleaning system by just pumping natural spawned chlorine on the asteroid into an airtight room. Once that's setup, there is really no use for chlorine pretty much ever again. It's not good enough to use as a cooling source, stresses out dupes if they run through it, and is nothing more than an annoyance. More often than not, finding a chlorine geyser just means having something annoying to try and build around.

** Cool Salt Slush Geysers are a new addition, one that is beloved for several reasons. Salt water serves as a more severe coolant thanks to its significantly higher thermal conductivity, meaning it can cool machines and the base faster than the polluted water from a Cool Slush Geyser. This actually serves to help it when it goes into a desaltinator, since it is too cold to be turned into ordinary water and will become ice instead, damaging the output pipe. Using it to cool the natural gas from a natural gas geyser or the natural gas generator and it's output is a viable strategy, on that does not require more than a bit of planning.
** Thanks to the addition of Buddy Buds and floral scent 'germs', Morbs have become the go-to way to produce Oxygen. Because of the way the game is programmed, no two sets of germs can occupy the same tile. By filling up a room full of Buddy Buds and then using uncleaned outhouses in said rooms to spawn a bunch of Morbs, as well as some deodorizers to clean up the [=CO2=] as it leaves the room, you now have a completely near 100% maintenance-free way to produce a bunch of oxygen without worry of slime lung pollution.

* LowTierLetdown: Among the geysers, the only one that's largely seen as more of an in the way eyesore than anything else is the chlorine geyser. Chlorine only has one very specific use; killing germs. Which is easy enough to set up a chlorine cleaning system by just pumping natural spawned chlorine on the asteroid into an airtight room. Once that's setup, there is really no use for chlorine pretty much ever again. It's not good enough to use as a cooling source, stresses out dupes if they run through it, and is nothing more than an annoyance. More often than not, finding a chlorine geyser just means having something annoying to try and build around.

* ThatOneLevel: Swamp biomes. Heavily populated with germs, and duplicants are almost guaranteed to get Slimelung from it, which can kill them if not dealt with quickly. It also can very easily spread through the colony like wildfire. What makes Swamp biomes so hard is that they often generate right next to the base; sometimes surrounding it on all sides, which makes it impossible to avoid. It is also the only source of Slime and Gold Amalgam, the former of which is necessary to make Algae (see Scrappy Mechanic above) while the latter is the best (unalloyed) metal to use to build machines that are likely to overheat.

* FanNickname: Mechanisms deliberately designed to kill animals (usually a flooded room which they can enter but not escape) are commonly called evolution chambers, the idea being that they accelerate their evolution into the ultimate lifeform - barbecue.

* ThatOneLevel: Swamp biomes. Heavily populated with germs, and duplicants are almost guaranteed to get Slimelung from it, which can kill them if not dealt with quickly. It also can very easily spread through the colony like wildfire. What makes Swamp biomes so hard is that they often generate right next to the base; sometimes surrounding it on all sides, which makes it impossible to avoid. It is also the only source of Slime and Gold Amalgam, the former of which is necessary to make Algae (see Scrappy Mechanic above) while the latter is the best metal to use to build machines that are likely to overheat.

* UglyCute:
** The dupes themselves. Also pufts and hatches.
** Heck, Puft Princes are this InUniverse, considering that they have a positive decor value.

** Steam geysers make water troubles a non-issue. While the water they put out is significantly hot, encasing them in insulated tiles or pumping the water to an insulated room just outside of your base negates the problem pretty handily. Bottled water doesn't heat things up too much, so the dups using it for that purpose isn't a problem and pumping the water to an oxygen producing room isn't a worry, as Electrolyzers always put out Oxygen at a fixed temperature regardless of the water pumped in, making cooling the oxygen the only real problem. Many people have managed to make fully self-sustaining colonies simply via steam geysers alone.
** In relation to the above, cool slush geysers output ''very'' cold water, with the only drawback being polluted, which is easy to purify. In addition to dealing with the usual water cooling problems, polluted water also makes for a very good heat sink. Either have the oxygen ventilation system pump through it to cool the hot oxygen output by the Electrolyzers or have the polluted water pumped to extremely hot areas of the base and have it act as a natural cooling system for the area.

** As of the December 14th, 2018 update, heat transfer is still a major problem. A localized area of heated gas will linger in one spot way longer than it has any right to (as opposed to the heated gas raising away). This can make a common, open area of your base have gas hot enough to burn your Duplicants, but it can take an entire cycle or two for it to cool enough to be safe. It's especially annoying in areas where Duplicants regularly pass through as they could be incapacitated just by walking through there a few too many times.

** In any given run, you're likely to come across at least ''one'' duplicant who seems to make a habit out of causing trouble; be it getting himself locked out of the base/trapped while building something, refusing to use the bathroom even if you have multiples open until it's too late or refusing to take a break at the massage table when their stress starts getting high. Naturally, these duplicants will quickly start to grate on you as time goes by.

** Hatches eat anything, including meat. They also drop meat upon death. You can totally feed a hatch the corpse of it's deceased parent. They are also good in starting bathrooms so they eat the polluted "dirt" that the outhouses produce.

** Steam geysers make water troubles a non-issue. While the water they put out is significantly hot, encasing them in insulated tiles or pumping the water to an insulated room just outside of your base negates the problem pretty handily. Bottled water doesn't heat things up too much, so the dups using it for that purpose isn't a problem and pumping the water to an oxygen producing room isn't a worry, as Electrolyzers always put out Oxygen at a fixed tempature regardless of the water pumped in, making cooling the oxygen the only real problem. Many people have managed to make fully self-sustaining colonies simply via steam geysers alone.

*** Deeper Diver's Lungs is even better, and a duplicant can have ''both''.

** Diver's Lung is widely regarded as ''the'' best trait a duplicant can have. Not only does it allow them to spend more time in oxygen deprived areas, allowing them to venture further out of the base before one gets exo-suits, it also lets oxygen in the base go ''way'' further than a colony of duplicants without Diver's lung. It's possible for a self-powered oxygen machine to make a large base of twelve or so duplicants easily breathable simply by a majority of those duplicants having the trait.

** Negative traits range from completely inconsequential to "never ever pick this dupe unless you're on a self-imposed challenge". In particular, Flatulent dupes generate small amounts of natural gas periodically, not enough to be useful for energy generation, but enough to screw with your plants, Narcoleptics drop anything they carry when they randomly fall asleep, Mouth Breathers and Bottomless Stomachs simply chew through two dupes' worth of resources, and those with Allergies will get '''extremely''' pissed off when exposed to Floral Scents (which pop up among certain common plants and brighten non-allergic dupes' days), practically guaranteeing they peak stress in a matter of seconds.

* CrossesTheLineTwice: If you don't have a memorial built and one of your dupes drops dead, the others will just leave their x-eyed corpse lying there and continue going about their business. They could be doing something like getting a massage or munching a muckroot next to their late friend's body. So wrong it kinda becomes hilarious.

* UglyCute: The dupes themselves. Also pufts and hatches.

* EnsembleDarkhorse: Of the possible duplicants that can be brought in, Mi-Ma is a fan favorite, thanks to her unique design (an old lady amongst the ambiguous twenty-somethings of the other duplicants) and rarely, if ever, having any major negative traits while usually having a lot of positive ones.

* GoodBadBugs: During the beta for the rocketry update, it was discovered that rockets destroy everything in their way when they launch off, including neutronium. Cue people using [[https://www.youtube.com/watch?v=zbFNaTeMKjc&feature=youtu.be&t=12m16s rockets in mass as makeshift drills.]]

* {{Headscratchers}}: If these dupes are here because Gravitas launched the printing pod onto the asteroid, how is there already an (abandoned) Gravitas office building on top of the asteroid?

** Thanks to the addition of Buddy Buds and floral scent 'germs', Morbs have become the go-to way to produce Oxygen. Because of the way the game is programmed, no two sets of germs can occupy the same tile. By filling up a room full of Buddy Buds and then using uncleaned outhouses in said rooms to spawn a bunch of Morbs, as well as some deodorizers to clean up the [=PO2=] as it leaves the room, you now have a completely near 100% maintenance-free way to produce a bunch of oxygen without worry of slime lug pollution.

** Negative traits range from completely inconsequential to "never ever pick this dupe unless you're on a self-imposed challenge". In particular, Flatulent dupes generate small amounts of natural gas periodically, not enough to be useful for energy generation, but enough to screw with your plants, Narcoleptics drop anything they carry when they randomly fall asleep, and Mouth Breathers and Bottomless Stomachs simply chew through two dupes' worth of resources.