Design and build
Everything in the colony is under your complete control. Build one large base, multiple smaller ones, use a symmetric design or make it functional, it's up to you.
Functional - Everything you build serves a purpose, from hulls that keep a breathable environment to oxygen generators, co2 scrubbers and advanced fabrication facilities.
Customise - Walls, Floors and Roof can be customised to look in any way you'd like. Colonists respond well to interior design
Gas system
Oxygen and CO2 - Reach optimal levels of oxygen and CO2 by building Oxygen Generators, Gas Scrubbers.
Toxins - Certain industrial processes will generate toxins that need to be filtered out for colonists to enjoy a healthy lifestyle
Temperature - Warm and cool your base as needed by building radiators and cooling modules, or just redistribute gas around the base for optimal comfort.
Power system
Use a multitude of power generators ranging from nuclear, solar, wind and even deep drilled geothermal stations. Use different kinds of batteries to store your energy from chemical to kinetic ones.
Large power grids require careful design to be stable. Manage both high tension and low tension modules with transformer modules between them.
Complex characters
Skills and Interests - Every colonist has a set of skills and interests. Use the priorities window to assign them to the right job and groom them to be they best they can be.
Mood - Colonists need food, oxygen, sleep, comfort and interpersonal relationships. A happy colonist is a productive colonist.
Mental brakes - If colonists have their mood down for too long of a time, they'll suffer a mental break. Some might just cuss at everyone while others might start breaking things or throw themselves out the airlock.