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