A Little to the Left

Unmissable - You need to complete all levels in Chapter 4 and if you complete all possible solutions (e.g. all levels with 2 stars or 3 stars have 2 or 3 possible solutions) you'll also get the One With Nature Achievement too for 100% completing Level 4.

This guide will help you through all puzzles and all achievements in the game.
All Chapter 4 solutions for One WIth Nature and Inner Nature Achievements can be found starting at Chapter 4 - 1:22:35.

A Little to the Left Walkthrough & All Solutions/Achievements

Simply finish Chapter 4.
For this achievement it doesn’t matter if you got 100% for every level, but I recommend doing that to save time & get the corresponding 100% achievement for chapter 4.