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