Here is the full list of all 50 Ori and the Blind Forest achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Complete the Prologue
Complete the game
A beloved bond
Fan the flames
Juggle a rock 5 times without it hitting the ground
Restore all Map Stones
Trick 5 enemies into killing another enemy
Enter Mt. Horu
Kill 500 enemies with Spirit Flame
Earn all Utility Skills in the Ability Tree
Find the lost corridor in the Misty Woods
Find 50% of all secrets
Climb to the top of Nibel
Save at every Spirit Portal
Collect 200 Energy Shards
Earn all Combat Skills in the Ability Tree
Have a close encounter
Restore the winds of Nibel
Clear the haze from the Misty Woods
Kill 100 enemies with Charge Flame
Restore 50% of all Map Stones
Create 50 Soul Links
Escape a dangerous situation
Cleanse the Ginso Tree's Heart
Enter the Ginso Tree
Make an unexpected friend
Kill 25 enemies using Bash to reflect projectiles
Cause an enemy to destroy itself
Crush a Ram with a Stomper
Kill 4 enemies simultaneously using Charge Flame.
Discover the character in the shadows
Break open 5 shortcuts using the Charge Flame
Kill 3 enemies without touching the ground
Meet the Ancient Being
Restore your first Map Stone
Use your first ability point
Find your first secret
Kill 5 enemies with Charge Jump
Find all secrets
Visit 100% of the map
Earn all Efficiency Skills in the Ability Tree
Earn all skills in the Ability Tree
Collect all Energy Cells
Collect all Health Cells
Bash off enemies 10 times in a row without touching the ground
Kill 50 enemies with Stomp
Finish the game in under 3 hours
Double Jump 5 times consecutively without touching the ground
Complete whole game without dying
Complete the whole game without using an Ability Point