Featuring single player skirmish games and multiplayer supporting up to 32 players, each empire can be customized with various genetic traits, ethical guidelines, travel methods, and cosmetic differences. Science ships are sent out with lead scientists (who level up) to survey planets for resources and habitability, to discover anomalies that can be researched, and to undertake special projects that trigger event chains. Colonizable planets are divided into tiles that can be manned by a population unit; buildings can be constructed to enhance the resources naturally produced by each tile. Pops can be allowed to migrate between planets and also form potentially dangerous factions (which can be combated with policies and edicts). Areas that cannot be colonized can still be mined for resources or research points (as long as they lie within the borders), giving “undesirable” systems an important use. There is a limit to how many planets can be directly controlled (which eliminates the late-game tedium of running a large empire); the remainder can be assigned to a sector, which is run by an AI leader whom automatically constructs buildings and gives an adjustable share of the resources back to the empire. Leaders can also conduct research and lead armies. There is no set research tree in Stellaris: rather, several semi-randomized choices (starting at three) are given at a time. Other empires can be interacted with, forming alliances, federations (an alliance with an elected leader), and trade agreements; ethical alignments influence relations greatly. War goals must be specified before a conflict starts, though the defender has a year to decide on their plan. Primitive civilizations can be studied for research points, while powerful fallen empires can affect the galaxy. Ships can be customized using the latest technology with the designer, or automatically upgraded designs can be chosen. Combat is automated, and planets can be invaded with armies after being bombarded from space. The AI seems to be very competent at managing an empire. Stellaris features a number of innovative features that makes it a very distinctive title in the space strategy genre.