Klei Entertainment

Lore & Background

In the fiction of Oxygen Not Included, the duplicants arrive on a colossal barge drifting through empty space, tasked with terraforming a hostile asteroid. The 'Director'—a disembodied voice—issues orders, and the duplicants obey, grow moods, form relationships, and occasionally die in slow motion while the player fumbles with a pressure valve. Klei Entertainment is the real-world hand behind that Director's voice: the studio that decided a colony sim could be as much about the emotional weight of a small person crying in a cramped room as it is about balancing CO₂ output.

The studio's broader catalogue—Don't Starve and its multiplayer sequel—established a design language Klei carried into Oxygen Not Included: hand-drawn, slightly unsettling characters; a world that is beautiful and lethal in equal measure; and a narrative that whispers rather than shouts. The barge is not a spaceship in the traditional sense. It is a terrarium. The duplicants are not astronauts. They are specimens, and the player is the glass wall they press their faces against.

Fans often note that Klei's writing avoids exposition dumps. Lore is embedded in item descriptions, in the way a duplicant's mood swings when they eat a raw mushroom versus a cooked one, in the small animated cutscene of a character staring blankly at a wall. The studio treats the player as an intelligent observer who will piece together the barge's history from fragments, much like an archaeologist reading a civilization's final, quiet days.

In Their Own Story

The barge hums. It always hums—a low, subsonic thrum that the duplicants feel in their teeth more than hear with their ears. In the deepest layer, where the bioluminescent fungi pulse in slow violet waves, a single duplicant sits cross-legged on a patch of moss, eating a cooked beet with the solemnity of a priest consuming communion. Above, three floors up, another duplicant is screaming into a pillow because the CO₂ meter just ticked past 30% and she can feel her lungs tightening. The Director's voice crackles through the intercom: 'Suggestion: consider ventilation.' The first duplicant chews. The second stops screaming. The barge drifts. Outside, the asteroid turns its grey, pocked face toward nothing. No one is coming. No one is leaving. The hum continues.

Reader's Guide

Klei Entertainment is not a playable species or Duplicant type; it is the design team whose choices define every species in the game. That said, their 'design DNA' is visible across all Duplicant archetypes.

Base Duplicants: No inherent stat bonuses or penalties. Moods are driven by temperature comfort (ideal 15–25°C), oxygen levels, social interaction, and food quality. Unique need: they must eat, sleep, and breathe, and their mood decays if any of those are unmet for extended periods.

Klei's design philosophy, as reflected in-game, favors systems interdependence over isolated stats. A Duplicant's 'happiness' is not a single bar; it is the sum of dozens of micro-conditions (room size, presence of a partner, whether they can see a window, whether their food was prepared by someone they like). This creates emergent drama without scripted events.

Species-specific restrictions in the base game are minimal by design—Klei chose depth of systems over breadth of species. The player's challenge is not 'which species do I pick' but 'how do I arrange 20+ individuals into a sustainable, emotionally coherent colony.' The studio's restraint is itself a design statement: fewer, richer systems beat more, shallower ones.

Did You Know?

• Klei Entertainment's earlier title, Don't Starve, established the studio's signature blend of hand-drawn gothic art and survival mechanics that Oxygen Not Included later translated into a 2D side-view colony sim.
• In Oxygen Not Included, the 'Director' voice that issues orders to duplicants is never shown on screen—Klei chose to keep the player's authority abstract, reinforcing the feeling of managing a terrarium rather than comma
• The barge in Oxygen Not Included is not a single ship but a massive multi-layered structure with distinct biomes per floor, a design choice that lets Klei showcase varied ecosystems (fungi, gas pockets, water cycles) in
• Klei's games are known for embedding lore in item tooltips and environmental storytelling rather than cutscenes, a technique fans call 'reading the room'—the barge tells its story through what's broken, what's overgrown,