The protagonist has two vital variables: health and oxygen. They are tightly interconnected. The astronaut needs air to breathe. One of the essential ingredients in the air is oxygen. It is also used to supply the level of health if the astronaut is wounded. In this case, he consumes the oxygen much faster (to refill the health bar, it may take more than half of the oxygen tank) since there are no medicine chests in the game, only oxygen canisters.
You might notice that most modern games do not feature an image of a red cross on any medical supply recourses. Usually, it is replaced with a stylized emblem that is close to the cross, but has other visual properties. This is because the red cross symbol belongs to International Red Cross and Red Crescent Movement. Because it has a specific and significant meaning, any misuse is forbidden by the law. This protects the emblem from contamination by unnecessary connotations and inflation of correct sense. Thus, other...