Here is the full list of all 13 The Pillar: Puzzle Escape achievements worth 1,000 gamerscore.
Complete the Gorge
Reach 70% high score in the Gorge
Find all art pieces in the Gorge
Reach 70% high score in the Maze
Complete the Maze
Find all art pieces in the Maze
Complete the Garden
Reach 70% high score in the Garden
Find all art pieces in the Garden
Reach 70% high score in Misty Hill
Complete Misty Hill
Find all art pieces in Misty Hill
Complete the Intro