@miles away earths atmosphere is actually nearly 30% O2

'Ox-i-t'

Oxygen is overrated

19.5% is the minimum amount of O2 a human can survive on in an atmosphere.
Current earth atmosphere rests around 20% or so.
If it's a terraforming gone wrong, there's a chance that there might be animals and plants that have been genetically modified for surviving in the new climate.
Now, there MIGHT be breathable oxygen in the air, but there could also be contaminants. A good example is Chernobyl. Nature has just about reclaimed that area, but ambient radiation is high-ish and the organisms there are surviving in that irradiated area as well. For all we know, it COULD be that exotic matter that's gotten into everything somehow and has done irrepearable damage to he environment. So breathing that stuff in could possibly cause some issues later on down the road, maybe not immediately.

Then again, it's a game. I'd rather wait for the devs to drop the lore than speculate any further.

Thank you .Great video. Helped a lot

Why does the player need to replenish O2 but there's elk, deer, bears, wolves.. oh, and TREES???? this makes no sense.

@Greeksayz It isn't that there is no oxygen. It is a terriforming gone wrong. The atmosphere may be a different mix. The animals are listed as having been adapted. That is why they can survive normaly, but your character can't.

And if they don't there is a lot of people that will bypass the game. When you leaving the space station to come to Icarus and you creating the character does't show nowhere that you have a helmet with oxygen, just a simple suit. There is no way that make sense that animals ,trees, plants , water and even berries exist without oxygen and you are not.Their talent tree and Crafting tree are awesome.

If they remove the oxygen feature it will become a classic survival game copycat xD

you need to remove the oxygen need in the Earth world. It doesn't make sense that animals survive and you can't. You need oxygen is bullshit.