Oxygen Not Included

Love this game but I am not smart enough for it so I usually go about 100 cycles and then reset

Tentative recommendation. Addictive, interesting, but idk if it's really for me. I love the simulation, but I wish that was more of a focus than gameplay and difficulty balancing. I think the main point of comparison is with Dwarf Fortress, which I think is superior in many ways. - DF makes losing fun and interesting as there's a bunch of ways that it can happen. ONI struggles in this regard. You're mostly dying from hunger (directly via a lack of food or indirectly via all your crops wilting) or lack of oxygen. Losing isn't fun. - DF has a large number of different builds. You don't even need to mine if you don't want to. ONI, while there are multiple starting environments, forces you to start with the very basics and then unlock more via a tech tree despite most of the tech being gated behind needing a specific resource anyway. In addition, what tech requires what resource is fairly arbitrary. Why do steam turbines require plastic? - It takes less time in DF to stabilise your colony and shift your attention from life support to vanity projects. in ONI you're stressing with life support for a long time. It's a great game for people who are okay with doing a lot of reading guides and doing things optimally, but that's not me. and I'm not sure I want to play it more than I have already.

If you're the kind of player who thrives on depth, complexity, and the thrill of solving problems with increasingly elegant systems, Oxygen Not Included might be your next obsession. After 1700 hours, I can say without hesitation: this game has earned every minute. Depth That Never Runs Dry What looks like a quirky space-colony sim quickly reveals itself as a brutally intricate simulation of thermodynamics, fluid dynamics, gas exchange, agriculture, industrial automation, psychology, and even rocket science. And yet, it’s all packed into a charming, side-scrolling aesthetic with expressive Duplicants and satisfying sound design. Even after thousands of cycles across multiple colonies, I'm still refining my designs, optimizing layouts, and discovering new strategies. There's no “one solution” — just more refined ones. Engineering Playground You’re not just surviving; you’re building systems. Water loops, oxygen production, heat management, food chains, power grids, automation, and late-game interplanetary logistics — this is a game where planning matters, and poor choices 100 cycles ago can come back to melt your base. Mistakes teach. Recovery is a puzzle. Mastery is satisfying. Endless Replayability Every asteroid type demands new thinking. Traits, biomes, geysers — all randomized. You’re never playing the same game twice. Want a relaxed experience? Play Terra and build at your own pace. Want a challenge? Start on Rime and deal with the cold. Or try modded asteroids and explore community-curated chaos. Systems Nerd Heaven If you enjoy games like Factorio, Dwarf Fortress, or RimWorld, but crave more simulation and fewer guns, this is your game. ONI is about processes. It’s a colony sim where how you do something is often more important than what you do. That’s a rare design choice — and it's beautifully executed. Minor Critiques The early game can feel like a trap for new players who don’t understand heat, gas stratification, or resource scarcity. Performance can drop in large colonies with lots of automation and piping. There’s no hand-holding — but the Wiki and community are incredibly helpful. Final Verdict: 10/10 Oxygen Not Included isn't a game you play. It's a game you inhabit. It's a slow-burn obsession for systems thinkers, tinkerers, and masochists who enjoy watching colonies implode because they forgot to vent CO₂. It’s also one of the most rewarding games I’ve ever touched. 1700 hours in, and I’m still asking: Can I make it better this time?

Yes, I'm giving this game a negative review after 500 hours played. Here is why. You cannot figure out how to play this game from any information available in-game, or from intuition, or from reasoning about real-world physics. All successful builds in this game exploit bugs, glitches, and undocumented behaviors that you could never guess on your own. The only way to find out how to build things successfully is to watch YouTube videos and/or read Reddit posts and use the builds there. The closer your builds look to theirs, the better they will work. This is a great game if you like copying what someone else did exactly because trying to think logically about it doesn't work. There are better and more transparently designed colony sims out there. Pick one of them instead.

The novelty of Oxygen Not Included is in the combination of colony sim with physics simulation based automation. That means, for instance, that carbon dioxide is heavier than oxygen, so you'll build your carbon-dioxide-consuming fungi farm at the bottom of your base. And if your building produces oxygen (yay) with a byproduct of hydrogen (oh no), then you build a tall room - like a chimney - and pump all the hydrogen into a machine that produces electricity from that. This example is just a small window into the many systems that the game offers, others include food, microbes, temperature, radiation, etc. And they all have interesting, free-form solutions. In a way, your colony is an ever-expanding puzzle box where you connect all these crazy contraptions that keep your colony just barely afloat. Failures will cascade across all systems. So you'll learn from your mistakes and build fail-safes. And then the fail-safes fail, and you start another colony. All this makes for a game that tickles the engineering brain. If you're into that category of problem-solving, this is for you.

I keep telling myself that I'll type a review once I master this one mechanic of the game or once I perfect this one system. The truth of the fact is there is always something else to master, something else to try to perfect and then fail horribly at. Every time I pick up the game I know it'll consume my every waking thought for days, weeks, months as I find myself researching and coming up with different layouts and designs every play though. Something special happens for me when I play this game, I keep saying its broken me because normally if its not perfect I'm not happy. A neat little colony in every other game and a place for everything and everything in its place, except ONI. In fact this last play through my Dupes are breathing polluted oxygen, there are no solid barriers except the rooms, the floors are made of random blocks, my only food source is from random pip planted crops, there is polluted water everywhere and dancing morbs in the bathrooms. Safe to say its a wild mess of a colony and I feel like its the best one I've had yet. Hey maybe the oxygen is polluted but its still oxygen! Slimelung you say? Nawww thats just a mild annoyance in comparison to the real threat of overheating my base. I'm over 800 hours in and I can say for a fact that I'm not even past the mid game part because I keep starting over for various reasons, mainly at this point trying to set up an aquatuner/steam turbine setup. But this doesn't stop me from enjoying every aggravating aspect of this wonderful game. If ever you've found yourself searching for that one game that'll make you work for every little step, filling you with such a deep sense of accomplishment that it just keeps you coming back for more, this is the game for you! I love it and quite honestly there isn't a game out there that is quite as perfect as ONI. Thank you Klei!

In this game, you can either become the next Newton, or watch funny little people suffer because of your terrible planning skills. 10/10

Really fun but complex game. I spent more time not playing the game looking at videos and guides.

I really wanted for this game to click. ONI is not Rimworld. It is not Factorio. It is not a physics simulator. ONI is ONI. And It is not fun. It's a game that teaches you by punishing. Each lesson is a colony-ending disaster disguised as 'progress'. You try to solve problem A. Problem B blindsides you and dooms the colony you spent six hours on. Restart. You solved A and B? Great. problem C shows up later. Restart. You solve A, B, and C? Congrats. Your “solutions” caused Problem F. Restart. There's no real satisfaction in restarting your 5+ hours colonies and reaching your previous prog point, only to actually """progress""" for an hour or so and doom yourself once again. You end up doing the same exact thing over and over, changing only tiny aspects of your build to try and patch whatever killed you last time. In other colony-sim games, your colony can get weird and janky. You struggle but it becomes a good story to look back on. Here? It's like trying to patch up a crippled horse that keeps kicking you in the balls for trying to help it. If you like CBT, be my guest. Restart. "Why not just look up guides and builds online, idiot?" Why not just let other people play the game for you then? I *did* try looking up builds. A lot of them rely on manipulating game mechanics and borderline exploits. It's stuff hard-coded into the game but unexplained. Where's the fun in that? So you either take the red pill and hopelessly try to copy these vague builds that you barely understand, or you go back to trying to figure out everything by yourself—oh, wait. Same thing with guides. There's not much in-between handholding or ambiguous do-and-don'ts. Yeah, I could spend another 300 hours trying to learn this game and make it actually click. Or I can...you know. Play literally anything else.

Ooops I guess I should probably review this game by now. I have been playing ONI since 2018. I have played many versions of this game and it just keeps getting better. I have never seen a Dev team so dedicated to adding fun improvements to their game after release! ONI in early access was awesome, but it is INCREDIBLE now. A complex game with so much to it, but you can learn and play at your own pace. I am not an automation game expert--I have learned a lot about automation game mechanics and have gotten more into the genre because of this game. In my opinion it is a very approachable game for folks not used to the genre--As long as you don't run out of any key resources for survival, there isn't a time limit (exception: the Prehistoric planet pack DLC). I am also a huge fan of the unique and diverse wildlife populations on the various asteroids (made more diverse if you have the DLCs too). I'll take all the Meeps and all the hatches. Thank you. Play this game.

My partner refers to this game as my second job. 10/10. You're looking for interconnected systems, complexity, and iterating to find the most elegant solution? Buddy, you've found it. Others have said it far better than I could, but if you're into systems management and want to sink a few hundred hours into a game, I can't think of a better one to buy.

Klei Entertainment’s Oxygen Not Included is not your average base-building sim. It's an unforgiving, complex, and weirdly charming descent into subterranean survival—where every breath, calorie, and molecule counts. Whether you're a colony management veteran or a curious newcomer, this game will test your systems-thinking like few others. At its core, Oxygen Not Included (ONI) is about building a livable habitat for your “Duplicants”—clones crash-landed deep beneath an alien planet’s surface. But calling it just a "colony sim" doesn't do justice to the sheer depth of its systems. You'll be managing oxygen diffusion, carbon dioxide buildup, temperature gradients, plumbing networks, food chains, waste disposal, morale levels, stress reactions—and even gas pressure and fluid dynamics. It’s part city builder, part survival sim, and part chemistry lesson, all rolled into a charmingly claustrophobic package. There’s no hand-holding. The game throws you into the deep end—sometimes literally into pools of polluted water—and expects you to figure it out. Trial and error is inevitable, and so are spectacular failures (exploding toilets, heat death, mass starvation). But when your systems work in harmony? It feels like magic. True to Klei’s style (see: Don’t Starve), ONI’s 2D art is vibrant and full of personality. The animations are expressive, and even under intense pressure, your Duplicants are endearing—until one has a stress breakdown and vomits all over the power cables. The UI is dense, but once you understand it, it becomes an indispensable control panel for your complex space ant-farm. This game is ridiculously deep. Want to build a hydrogen-powered cooling loop using wheezeworts and radiant pipes? Go for it. Want to establish a slickster ranch to convert carbon dioxide into oil? Totally viable. Eventually, you’ll be building nuclear reactors and rocket colonies. And with randomized maps, custom asteroid traits, and dozens of viable build strategies, no two colonies play the same. The sandbox potential is massive for those who enjoy experimentation and iteration. Here’s the catch: ONI is hard. The early game is punishing, the mid-game is overwhelming, and the late-game is basically an engineering thesis. This won’t appeal to everyone, and even fans of the genre may bounce off if they expect a relaxing city-builder. It’s more Space Factorio than Stardew Valley. Still, the difficulty feels fair—like a puzzle you want to solve, rather than a wall designed to block you. Pros: -Incredibly deep and satisfying simulation -Charming art and surprising humor -Huge variety of systems and mechanics -Excellent sandbox and creative potential Cons: -Steep learning curve with little onboarding -Can be overwhelming in mid/late-game -Performance dips with large colonies Oxygen Not Included is one of the most intellectually engaging management sims ever made. It challenges you to build not just a base, but an ecosystem—a finely tuned machine where failure teaches as much as success. It’s dense, demanding, and deeply rewarding for those who love complexity. If you’ve ever wanted to manage a tiny society on the edge of suffocation with a smile on your face, this game is for you. Perfect for systems engineers, base-building addicts, and people who think thermostats are fun. Rating: 9/10

I have a love hate relationship with this game, makes me feel like a total stupid person, but its also rewarding as hell when you figure something out, its incredibly deep, and very addicting, which is why i hate it at times, because i fail so miserably but then it gives me just enough to hold on. i have barely scratch the surface, i dont think ill ever be a pro at it, or that ill play that much more but i really had a great time with it. maybe will pick it up again when i feel like less of a loser lol . i mean ive already sunk 40 hours plus 10 hours of youtube tutorial and i still dont understand much.

one of those games that makes your brain feel like it's overheating – in the best way possible. There's a steep learning curve, and at times it can feel overwhelming trying to balance oxygen levels, manage resources, and keep your duplicants alive. But once you start to understand the systems, it becomes incredibly rewarding and oddly relaxing in its own chaotic way. The depth of gameplay and the satisfaction of building a functioning base make it hard to put down. It’s stressful, challenging, and at times absolutely brutal – but it’s also one of the most fun and addictive colony sims I’ve ever played. If you enjoy problem-solving and don’t mind failing a few (or many) times while learning, this game is definitely worth your time.

Good game, will become more complex over time and take more time to learn then you first thing. Don't free mistake as you can save as much as you want. And don't forget to restart if thing seems hopeless and use what you now know to do better. Experiment and experience success and failure is how you learn. Many more will suffer for my need to learn more, so others can prosper later.

It's a fun colony sim, not too difficult to learn and offers decent challenge ime

I was very skeptical because of the graphics but the game design and highly technical structure is so fun. It is difficult, but that's what I like about it. Buy it.

Adorable game that's really difficult, but super fun to replay every now and then. I can only recommend!

Amazing game, if you like organising, efficiency and a real challenge play this game, if you manage to make it to the end without looking at any guides you are way too smart simple!

Obviously a majority of the people playing this game give this game a thumbs up - given the Overwhelmingly Positive reviews on steam. I thought that this game would provide the same level of "time dilating" immersion I've experienced with Rimworld, it wasn't the case. My first three hours were slow, uninteresting, and all-around uneventful. Maybe I've been spoiled by Rimworld. But I just don't think I can enjoy this game. That said, if you have played and enjoyed Rimworld, I'd say its worth a shot - especially at sale price.

Fallout shelter pero mejor. Añadan multiplayer default, rancios.

The game really looks fun but HOLY you get so overwhelmed when you enter it. A bunch of keywords and things to do that are not explained. Really thought I would like the game but the lack of explanation just destroys it for me. My head hurts after trying to understand how I did things. Overall, if you don't mind watching a youtube tutorial go for it, but not a game for me

Got to around a population of 20 and i'm looking at the research tree going, I don't want any of this stuff, it sounds like a pain to setup. Basically I recognize flaws in my base that organic-ly grew that way, but the rework would probably take 20 + ingame days. Which is several hours. I think one big issue with the game is you look back and see 4... maybe even 8 hours have passed, because you are having fun, then you look back at the game, and you have like 6 new rooms. You don't really have a good opportunity in the game to expand/explore outwards in specific directions in a reasonable amount of time or maybe that is the major flaw of how I played. Also the research tree is kinda fake. All Tier 1 upgrades are pretty much required, so choice is fake here. Then you get into T2 + and it feels the same way, but then you realize a lot of the research starts focusing on logic gating, which is always a pain to learn in a new game and setup.

This game is an excellent, challenging base-builder perfect for those of us who love mega-basing! It is a low-combat, high-resource management sim with potential for dozens of ways to challenge yourself and explore the map!

Its been fun, especially if you take the time to figure out how to take advantage of the tile physics and "nature" to do things rather than just using machines.

accidentally burned my whole colony to death when I tried to repair my infinite natural gas storage

One of the best games I have ever played that still constantly gets new updates and DLCs for a low price. If you like spending hours on hours thinking, planning and calculating, you will love this game - guaranteed.

I seem to always fall back to this game. Its challenging, its addicting, and at many moments frustrating - which is all the reasons why I probably keep coming back to it! If you are looking for a more challenging colony sim, look no further!

Oxygen Not Included is a very fun challenging colony simulator. It took me a long time to figure out how to do things effectively in the game, but once you figure out how the various systems interact with each other, it becomes a very addictive sandbox. For those struggling to learn, I highly recommend the "Tutorial Bites" series of youtube videos by "GCFungus" Those really helped me learn

“What it Rimworld was in a side perspective, and the endgame boss was cooling systems” Yes.

Been playing this game on and off since 2017. Super amazing art! I always end up getting distracted with digging and expanding too fast lol

there are funy litle critters and they are cool abd i will protect thenm

It's a fun game but the management is literally driving me insane. I finish plumbing, wiring, and automating my base only to realize I've put the water intake pipe into the outlet pipes for the bathrooms. To undo this I have to deconstruct all of the incorrect parts, which dismantles everything, and so I have to rewire, re-plumb, and re-automate everything in the spots I deconstructed. Not to mention the time it takes for the little guys to actually do all of this stuff. I even started playing on sandbox because it was driving me so insane. It didn't help. My play time is 90 percent building and re-building and re-building stuff while paused in sandbox. There's just too many resources, too many liquids, too many ores and stone types, too many miscellaneous solids, too many different things to collect to build too many other things. Everything needs something different. I had a lot of fun, except for when I quit out of frustration a billion times after making a small mistake which ruined everything I had going, or restarted a billion times, because one small detail was out of place and I had to demolish so much stuff. Take this with a grain of salt though cause I have pretty severe OCD. My fiancee is playing it and having a good time, because he just builds whatever wherever and doesn't need everything to be pretty and perfect and completely optimized. but I have to uninstall before I completely lose my mind. So I don't recommend if you're like me, but most people will maybe find it fun? It makes me miss the simplicity of Rimworld though. At least they only have one liquid that matters (conquest!)

So I actually put this game on ignore for several years. I couldn't stand the look of it. I played Don't Starve Together for years, but the Together part of it was a huge appeal for that game and the overhead. This weird looking platform single player game just didn't fit, but... it hit a discount and there a a few people I know who really seem to enjoy it. That's where I fit in too. Now I do play games like Rimworld, and tapped my toe in Dwarf Fortress, so love colony style games as long as the GUI isnt' too bad, that's why I waited so long for DF. So Oxygen Not Included has a fairly steep learning curve, but it does what these colony, survival, get a good system going or watch it cash does best. No 1, it is absolutely excited to start a new world and see what you get. As you open up new things, you do learn by trial and error how it does or does not work. It's fun to restart and apply that knowledge. There is some room for error. You can recover from imperfect choices, but you could also fail from terrible choices. But here is where it falls a litle flat to me... these duplicants meant nothing to me. They are not varied enough by looks. They don't stand out to me in anyway. because it's platform i've seen 3 or 4 of them just walk lock in step and I didn't even know it was a blob of them moving together. In games like Rimworld, I know my peeps, down to their name, what they're wearing, how long I've had them, what relationships they have with each other. I find none of this year which is often a huge part of colony simming, for me, but...the nature of the sytems you build overcome this shortcming. It's just fun to see water, sewage, different gases, and what not go through pipes and vents. These other games have it but not in that depth so... I will recommend it. I've got a long way to go to learn more and do it better, but there is depth here and if a game is fun to play on repeat, it's usually a great sign. If you were like me and kind of passed over this goofy platform thinking it just didn't appeal enough, maybe give it a go the next time it pops up on sale. Who knows, I might even be in the market for the DLC this game has by the time you do.

Klei introduced me to Don't Starve thinking that they couldn't possibly keep getting away with trying to kill their players in the guise of their amusing and comedic artstyles but this one takes it by a mile. So much of this game requires you to really plan ahead and manage even the smallest of things, like Pei eating the entire colonies food supply because her tootsies got wet or Abe destroying the place because somebody snored right next to them while trying to sleep. The temperature that creeps up on you slowly, thinking that you got every necessary resources figured out. This game either makes you smarter and plan out your every move or it just blatantly points out your horrible colony management skills. The constant loop of problem-solving ONI provides brings a never-ending addiction to trying to brute force your way to success. 10/10 game, would reset worlds every time something goes wrong

When you first start it is hard, and you will start over a lot. But it gets better.

it is so mutch fun and i absalutely love the animation style i am stiil in mid game but i alredy have to recomend it

Leaning curve is steep, first few runs will die quick, know that it is ok to decide to start over. starting out i recommend getting outhouses, washbasins, beds, and a science table by end of day one if you can, there is enough oxygen included to keep dupes alive for the first night if you cant get that under control. The game has a lot of layers of complexity and does not drop random bombs to make things difficult, in the end you make things difficult by solving a problem that creates a new (less obvious) problem that grows until you notice and deal with it. I.e. running low on air so you make a lot of oxygen, then a while later you realize you are out of algae because you made too many.

Well hell yeah, it is a fun game and has plenty of detail and depth, each new game you start makes you better.

This game is so addictive, I love it! It's awesome. Every time you discover something new, it makes you want to keep playing

this is a game where everything has a freezing and melting point, including duplicants and your own brain

This game is incredibly fun, playful and challenging - I really recommend it. My one challenge would be on the performance side, as even the cartoon graphics really rev my (5 year old) PC when the base gets big. Perhaps there are ways to batch calculations more or otherwise optimize.

Always ignored this game because I tought it's 2d rimworld from Klei (not a big fan of their titles). In reality this a very different: it more like liquid/gas management puzzle, where colony sim randomness is done not via random events, but via unpredictable physics of those substances.

One of the first games I purchased since I got my SteamDeck 4 weeks ago. This is a game that just keeps giving. Even after over 40 hours of gameplay, I still have a lot to learn and instead of it being burdensome to learn, they made it so rewarding and satisfying instead. I'd give this game a hundred stars if I could.

great game but difficult to master, you need to be able to think of what you are doing and what your going to be doing and ive failed more times than i can remember but still i great and fun game.

Very addictive, and personally I find it quite hard! I cannot go a save without killing one (or many) of my dup's before getting to the surface! It is challenging but enjoyably so!

This is the most simple and yet complex sim game I have played. So much to do and learn.

Been watching folks play it off and on all the way back to it's early access days. Don't know why it took me so long to actually pick it up, but I haven't put it down in the week or two I've had it. If you know what the game is and you're on the fence, I say take the plunge. If you're only just hearing about it and want to know more, there are a bunch of brilliant streamers and LPers on twitch and youtube who can do a better job of showing you the game than I can do in a blurb here.

Heard good things about this game. Honestly I don't know when I put it on my wish list. I've played base building games like Dyson Sphere Program, the Sim Cities, and several more. For $7.50 I thought this would've been along the same idea of Fallout Mobile, I was wrong . The artwork is similar, so I assumed the learning curve would be short (I was wrong! ) This game is fun and simple in the beginning, then the learning curve rised sharply. That's not a problem at all, but I watched a guy on YouTube, copied his video and was good. Until the "seed" I used did not have the same amount of food that was hidden in the rocks! I spent hours learning the early game, somewhat grasp the mid game, can't even fathom the late game with rocket ships! I'm all in and will eventually launch a rocket to the next asterdoind. 9/10 (just my occasional frustration) 8/10 On Steam Deck (where I played all my hours, just learning the control scheme)

Wow, this is definitely a unique game in its presentation. There is nothing else out there quite like it. I've played a lot of OpenTTD (transportation sim). The micromanagement of everything in ONI reminds me of OpenTTD. It's not an easy game, but the learning curve isn't too steep if you're willing to watch some videos or read. I call this the big brain game. So if you like sims that make you think and you learn something in the process, ONI is for you.