Oxygen Keep the last breath flowing

Everything starts with the Oxygen Center. It makes oxygen by electrolysis of underground water, and electrolysis needs electricity, and electricity means coal. Feed it steadily and your city lives. Let the power dip and the air runs out.

That single dependency shapes every decision. Coal is reliable but finite, and the game pushes you toward sustainable sources over time. You weigh a new coal plant against wind and solar, knowing a storm can double your energy use without warning. One bad night of planning and the thing keeping two hundred people breathing goes quiet.

The disasters here are not weather flavor. Deadly winds raise the toxic gas concentration, and anyone caught outside in it gets sick. Crack explosions open new fissures that leak poison but also hold energy you can extract. Droughts and frosts cut off the lakes and rivers your people drink from and fish from.

The counter is stockpiling. Before a frost, you fill warehouses with water and food. Before a wind, you bank energy and keep everyone under oxygen supply. Each disaster asks you to change the settlement's priorities, so there is rarely a quiet stretch where nothing needs doing.

Your settlers are not just labor units. An uneducated, unmotivated worker runs at a fraction of full productivity, so investing in people pays off like any building does. Schools, decent living conditions and research raise confidence and education, and educated settlers work several times harder than their parents did.

There is a catch, and it is the vote of confidence. Once a year your people judge you on comfort, buildings, research, quests and the trees you have grown. Miss the target and a tenth of your population walks out the gate. It is a slow, patient game about earning trust as much as producing goods.

For city builder fans, the pleasure here is layout under pressure. Buildings placed stay placed, so every road, warehouse and housing block is a commitment. You learn to cluster production near storage, tuck homes around oxygen-producing trees, and keep walking distances short, because a long commute in toxic wind is a one-way ticket to the hospital.

There are five maps with their own challenges, adjustable difficulty from casual up to a sandbox Build mode with all research unlocked, and full custom settings for colonist count, tasks and production speed. You can tune the world to be exactly as harsh as you want it.

As a colony sim, Oxygen runs on generations. Settlers age, children take a long time to grow into workers, and the yearly confidence vote decides whether anyone stays. Births barely outpace deaths, so a colony can look full while its workforce quietly shrinks.

Your job is to keep the pipeline going: assign workers where they are needed, keep the sick from spreading disease, educate the young, and complete the tasks that earn trust. Stories come from what goes wrong, and here what goes wrong is usually arithmetic. Too few adults, too many children, one drought away from a bad year.

The wasteland is stocked, just not generously. Signal towers reveal points of interest around your settlement, and you send teams out to explore ruins and abandoned areas, collecting materials and rescuing survivors who join your city. Expeditions cost canned food and water, and the sites are finite, so early scavenging is how you afford the tech that makes you self-sufficient later.

There is a quieter kind of salvage too: the dead trees scattered across the map. Revive them, dome them, and they produce oxygen for the buildings clustered around them. A green pocket in a gray world, built one sapling at a time.