In order to get the achievement Home At Last you need to defeat the final boss and collect 5 fuel cells (you can skip the final boss fight in order to get the achievement Screw This Noise)
Items required to launch from the planet
- The Planet Seed (you get this after defeating the final boss and is only required if you just want Home At Last achievement)
- 5 fuel cells
It doesn't really matter in which order you do it but if you want the Screw this noise achievement then don't fight the final boss just get the 5 fuel cells to leave the planet
Video guide on the 10 fuel cells locations