Here is the full list of all 23 Still There achievements.
Watch the credits
Complete the game
Begin Final Chapter
Restore the electricity supply
Begin Chapter Five
Hide the Bento
Fix the oxygen leakage
Take care of the tuatara
Begin Chapter Four
Fix the Cooling System
Begin Chapter Three
Decode the mysterious signal
Wash your teeth
Begin Chapter Two
Drink coffee
Begin Chapter One
Give a funeral to your little friend
Take Gorky out with you
Win a chess match with Gorky
Eat milk
Drink five coffees
Open the menu during fake credits
Draw a tally mark for each day on the Bento