Oxygen Not Included

''Oxygen Not Included'' is a 2019 survival simulation video game developed and published by Klei Entertainment. After being released on Steam's early access since February 2017, the game was officially released on July 30, 2019.

Gameplay

''Oxygen Not Included'' is a simulation survival game. At the start of a new game, three colonists (referred to as duplicants) find themselves in an asteroid with isolated pockets of breathable atmosphere, with no memory of how they got there. The player is tasked with managing and taking care of these duplicants as they try to survive and create a sustainable makeshift space colony. The player must monitor the duplicants' hunger, waste, and oxygen levels to keep them alive. Each game's world is procedurally generated. The world is then subdivided into various regions or "biomes" that contain different and often biome specific materials and critters. While initial areas have a breathable atmosphere, subsequent areas are in a vacuum or lack oxygen, requiring proper preparation by the duplicants before they explore these areas. The world also contains several hazards such as diseases and extreme temperatures. The game simulates the diffusion of gases and equalization of atmospheres when a new natural chamber is opened, which can cause oxygen levels to drop in existing chambers, as well as the draining of liquids by gravity.

To help establish the colony, the player directs the duplicants to perform certain tasks, such as mining for resources, growing food, crafting equipment, researching new technologies, and maintaining their own health through nourishment, rest, and hygiene. The player does not control the duplicants directly, and instead provides prioritized instructions, from which the duplicants will then follow to the best of their abilities. For example, the player can order a conduit of wire to be built; which will have the duplicants collect the materials to make the wire, clear away any materials around the conduit's path, and then construct the wire. If the duplicants cannot access a source of copper for the wire, the task will remain uncompleted as the duplicants go to complete other tasks they can do. Duplicants have stats that determine how effective they are at certain tasks, and will prioritize tasks that they are best at. These duplicants' skills can be improved over time and practice.

Development and release

''Oxygen Not Included'' is developed by Vancouver-based indie studio Klei Entertainment. The game was announced for Windows during the PC Gaming Show at the Electronic Entertainment Expo 2016. It was also revealed that the game would come to macOS and Linux. An in-development version of the game was made available via early access on February 15, 2017. The game was originally stated to leave early access on May 28, 2019, but was pushed back to July 2019. Klei also announced plans to make downloadable content for the game. DLC has since been added, such as the free Automation Innovation update (extending the current automation system, adding equipment such as ribbon cables) and the paid Spaced Out update (adding a radiation system, uranium refinement, and bee ranching). Klei has stated that there will be no more DLCs for ''Oxygen Not Included'' going forward, opting for free updates instead. That being said, the game then released two extra DLC packs years later: ''The Frosty Planet Pack'' on July 19, 2024, and ''The Bionic Booster Pack'' on December 13, 2024.

Klei's Johann Seidenz said that games such as ''Dwarf Fortress'', ''Prison Architect'', and ''The Sims'' influenced the design of ''Oxygen Not Included''.

Lore of the game

Through playing the game, by 'inspecting' certain pre-existing structures laid out randomly throughout the map, players can discover and put together story elements (also referred to as 'log entries') of the ''Oxygen Not Included'' universe:

Setting

The events of ''Oxygen Not Included'' take place in the distant future (potentially during the 23rd century). The Earth has suffered catastrophic environmental degradation. Fossil fuels have been depleted, nuclear energy is highly restricted, and the atmosphere is choked with pollution. Conventional solar power is insufficient, and global conflicts over resources have intensified.

Gravitas

In response to the escalating ecological crisis, Dr. Jacquelyn Stern founded Gravitas, a scientific research organization dedicated to solving the energy crisis. Gravitas quickly became a powerful institution, producing technologies such as molecular forges and thermal nullifiers. However, its core objective was much more ambitious: enabling time travel and interstellar colonization.

The centerpiece of this effort was the Human Colonization Initiative, a project aimed at establishing human life on distant, potentially habitable asteroids. To address the logistical challenges of transporting materials and personnel via spacecraft, Gravitas developed Printing Pods—devices capable of 3D-printing infrastructure, resources, and even sentient workers directly on arrival.

Genetic Engineering and Duplicants

To further support extraterrestrial colonization, Dr. Olivia Broussard, a geneticist and former colleague of Dr. Stern, was enlisted to engineer lifeforms suited for survival on alien planets. These organisms—including plants, animals, and microbial life—are found throughout the game and are assumed to be biotechnological constructs developed at and by Gravitas.

The workforce for these colonies consists of Duplicants, artificial human-like beings created through biological printing technology. Initial experiments involved non-human DNA, but human genetic material—often sourced without consent—was soon incorporated. Many Duplicants are clones or imitations of actual Gravitas employees. Due to security concerns, biometric locks were installed in the Gravitas facility to prevent the originals from accessing certain areas.

Gravitas' collapse and abandonment

At some point, Gravitas experienced an internal disaster. Clues scattered throughout in-game ruins, such as corrupted logs and malfunctioning equipment, suggest a containment failure, possibly linked to overuse of teleportation or cloning technologies. The facility was abandoned, and the project was never completed.

The player's colony is one of the surviving automated outposts, activated long after Gravitas's fall. The Duplicants operate without direct oversight, guided only by the systems left behind.

Asteroid Colonies

Each game begins with Duplicants arriving on a randomly generated asteroid, referred to in-game as a “planetoid.” These asteroids are artificial environments seeded with Gravitas-engineered ecosystems, machinery, and infrastructure. Although they appear naturally formed, many elements—such as perfectly rectangular ruins, mechanical POIs (points of interest), and printed resources—imply that they were prepared or altered by Gravitas prior to the catastrophe.

These planetoids often contain remnants of Gravitas installations, including research stations, laboratories, and transit tubes. The presence of automated message terminals and storage lockers containing personal effects indicates that Gravitas employees once lived and worked on-site. Some asteroids also feature temporal tear anomalies, suggesting experimental teleportation or time-manipulation technologies may have destabilized local reality.

The Temporal Tear and the Universe's Fracturing

One of the core mysteries of the game is the Temporal Tear—a cosmic rift discovered in the late stages of gameplay. In the ''Spaced Out!'' DLC, players can construct rockets and travel to other asteroids, eventually building a Temporal Tear Opener. Once activated, this device allows access to a realm beyond conventional space-time.

Lore fragments suggest that Gravitas’ experiments with teleportation and time travel may have damaged the fabric of the universe. The Temporal Tear appears to be both a symptom and a byproduct of these experiments. Some speculate that the Duplicants’ continuous existence in isolated pocket-dimensions may be the result of a fragmented reality, where time loops, causality breaks down, and remnants of Gravitas’ projects continue functioning in isolation.

Post-Gravitas Autonomous Operation

The game world implies that Gravitas’s infrastructure, including Printing Pods and research computers, continue to operate autonomously. Duplicants are printed without external commands, suggesting a failsafe or self-preservation directive. As there are no signs of external communication or central oversight, each colony is effectively a self-contained experiment or survival scenario.

This autonomy is reinforced by the absence of any surviving human authority. Although Duplicants bear the names and appearances of Gravitas employees, they have no memories of their predecessors and operate more like programmed entities than true individuals. Whether this was Gravitas’s intended outcome or a consequence of the organization's downfall is left unresolved.

Reception

Reviews

Review aggregator Metacritic gave the game a score of 86/100, meaning "Generally Favorable".

Nate Crowley, writing for Rock Paper Shotgun praised the game's design and progression, but questioned the ever-growing complexity as a deterrent to more casual gamers, especially those without backgrounds in science and engineering. GameCentral also gave the game positive reviews, with a total 8/10, praising the scientific accuracy as well as the design, but raising concerns about the difficulty, especially with the lack of in-game learning tools.

Accolades

''Oxygen Not Included'' was nominated for " Strategy/Simulation Game of the Year" at the 23rd Annual D.I.C.E. Awards, and for "Strategy/Simulation" at the 2020 Webby Awards.

References

External links

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{{Klei Entertainment

2019 video games
Early access video games
Klei Entertainment games
Simulation video games
Survival video games
Video games developed in Canada
Windows games
Linux games
MacOS games
Indie games
Single-player video games