Oxygen Not Included is an extremely successful space colony simulation game by Klei Entertainment. It has been in early access since 18th May 2017 and the full version includes three new biotopes, more buildings, and additional creatures. Players need to manage their colonists and help them dig, build and maintain a subterranean asteroid base - the inhabitants need water, warmth, food, and oxygen to keep them alive. The little complexity monster with its charming and almost harmlessly cute comic presentation is a surprisingly sophisticated and complex colony construction and management simulation.