Oxygen Not Included (v744825 & ALL DLC)

A cramped asteroid becomes a remarkably deep survival sandbox where every breath, meal, and degree of heat matters. Oxygen Not Included is a colony-management simulation built around keeping a growing crew of Duplicants alive inside a sealed, hostile underground world. Its cheerful cartoon presentation masks a demanding systems game: a misplaced generator can fill living quarters with carbon dioxide, while one poor plumbing decision can turn clean water into a colony-wide health problem. The tone is equal parts playful and ruthless, rewarding experimentation but never ignoring a preventable disaster.

Players excavate layered biomes, assign jobs, and construct the infrastructure that keeps daily life running. Duplicants need breathable air, food, beds, sanitation, power, and protection from extreme temperatures, but they also bring individual traits, skills, stress reactions, and inconvenient habits. Every material behaves differently, so gases rise or sink, liquids flow through pipes, heat transfers between machines and rooms, and polluted environments create problems that demand clever engineering. Research unlocks better technology, while expanding beyond the starting pocket forces difficult choices about resource consumption, automation, and whether the colony can support another new arrival.

What separates Oxygen Not Included from more straightforward city builders is its obsession with interconnected simulation. A successful base is not merely attractive or efficiently laid out; it is a functioning ecological machine with air filtration, waste processing, cooling loops, electrical grids, farms, and increasingly elaborate automation. Failures often become the best lessons, making each restart feel less like punishment and more like a new engineering challenge. Fans of RimWorld, Factorio, or complex management games should find plenty to obsess over, while newcomers who enjoy learning through trial and error can start small and gradually grow into its demanding but deeply satisfying systems.