Stage 4 has been in development for a few weeks, and most of that time has been spent figuring out how to write it. It is the final stage of the game, and features your character in their twilight years. Essentially it involves making choices about how you feel you've spent your time, whether you have regrets, and how to best ensure people remember you after you are gone.
Following this it will be possible to play the game from start to finish.
It is recommended to start a fresh save.