The game tasks the player with building and operating their very own space station filled with beings, the needs of which you will have to meet.
Players start off with three beings and will have to build, mine and expand upon the station, all the while dealing with whatever the universe throws at you: sickness, asteroids, and the like.
The team has all sorts of thing planned for the game along with additional goodies it would like to add to it over time - all posted through the link.
Double Fine has released a wiki on the game, showing all sorts of things included.
If you drop $25 you will get a copy of the Alpha build for PC, Mac, and Linux; however there are other tiers available which offer more.
Project lead JP LeBreton has produced a trailer detailing more about the project and it is posted below alongside the Early access launch trailer.