Here is the full list of all 12 Always The Same Blue Sky... achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Travel to an undiscovered land
Endear yourself to Kira as much as possible
Alienate yourself from Kira as much as possible
Reach ending 2
Take note of your surroundings
Reach ending 1
Demonstrate a firm scientific grasp
Visit the ancient courtyard
Try 2 different milkshakes
Captivated by what could be...
A burning fire
A calming glow