Colonists are accurately simulated down to body temperatures, emotional states, respiration and perspiration rates, social preferences, metabolic speeds, fatigue levels, photosensitivity, and specific British social anxieties.
Every attribute affects their behaviour in the colony. A very tired colonist will become irritable and make poor choices. A very hungry colonist may die.
The scientically accurate detail pervades the simulation. Objects throughout the world interact and behave in realistic ways.
Plants grow when exposed to light, atmosphere diffuses from room to room, electronics fail when infiltrated by water, and equipment burns when it gets too hot. As do colonists.