Assuming its major update status, Biotech sees the addition of three novelties fundamentally changing the basic game: the possibility of raising children and creating families, the ability to genetically modify all this little world, and finally the possibility of controlling mechanoids, settler-machines controlled by a central entity. All this, of course, in the service of a colony more efficient and better armed against the perils of the world.
As in real life, raising children is a drain on resources that makes societies more fragile, but pays off in the long term with new workers who can be forced to work at will. It will therefore be necessary to create a nursery to welcome them, but also to provide them with something to play, educate and feed themselves. Fortunately, it is possible to accelerate the growth of toddlers in a capsule making them grow faster. Unfortunately, the process is not as effective as letting them discover the world over the years, which makes it possible to select traits and passions to develop for each child.
For fans of augmented humanity, it will also be possible to designate a colonist to become the mechanism, a human with a brain modified to control machines by thought. Connected to machines from his sarcophagus, he will be able to grow mechanoids in incubators, creating an army of robots ranging from simple workers to laser-wielding centipedes to gargantuan siege machines. Like all machines, they obviously create significant pollution that contaminates humans and animals, blocks light rays and alters flora and fauna. Managing pollution will become important: for example by dumping it on neighbors, as in real life.
Finally, genetic modifications make it possible to create all kinds of funny mutants, from people with blue eyes (who are indeed mutants), but also those capable of breathing fire or becoming immortal. As a result, we will find in the game factions of modified human xenos, real monsters controlling corners of the map. All these genes can be combined and modified at will, and it is of course possible to harvest them from the corpses of your enemies.
Biotech will be available in a few weeks, but this version 1.4 of RimWorld is already available as a beta branch on Steam. Other changes are also to be counted: loading times improved by 37%, the possibility of choosing the color of its decoration, the all new presence of architectural styles, storage shelves, two new types of turrets, management decomposing bodies, etc.
All of these new features, their in-game appeal, and how they were crafted by the developers are detailed in a very, very long Steam post from Tynan Sylvester.