I'll repeat my answer from your previous question:
Dweller is a game that features "perma death". This means that when you die you die (and hopefully learn something from the experience). Perma-death is quite common among games such as Dweller and it's not something that I plan to change.
NOTE: The game should autosave when you quit and load again when you start the game. But, as I said, when you die your save is gone.
