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