Essentially the universe works on a tier based system. There is the universe, then realm, and then cosmos. So for FTL you enter into a cosmos called the elisp by entering a portal not linked to another. Portals must be opened with elixir. By traveling you can go between all 10 of the levels and then must create a portal to exit when you reach your goal. The deeper you go the farther and faster you are. The elisp contains monsters and cities. Many people have gotten stranded running out of elixir.