Here is the full list of all 14 The First Tree achievements. It takes around 4-5 hours to unlock all of the achievements on Windows.
Finish the game
Find your name again in a familiar place
Uncover all secrets and discover a priceless treasure
Collect all 150 stars
Uncover all main items in the game
Find all 5 secret items
Collect 100 stars
Reveal the king of the rabbits!
Activate all of the obsidian rocks and unlock the way
Find your name
Find a secret item
Collect 50 stars
Dig up your first item
Catch your first bunny