Here is the full list of all 12 The Almost Gone achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Finish chapter 1.
Complete the tutorial.
Finish chapter 2.
Finish chapter 3.
Finish chapter 4.
Finish the game.
Finished the game a second time
Completed a puzzle by cheating or guessing.
Look through a telescope for more than 2 minutes.
Spend more than 5 hours in the game.
Spent more than 30 minutes in Emily's room.
Combined the dog and grave on house number 2.