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
Kill 25 enemies using Bash to reflect projectiles
Collect all Energy Cells
Enter Mt. Horu
Earn all Combat Skills in the Ability Tree
Find the lost corridor in the Misty Woods
Earn all Efficiency Skills in the Ability Tree
Climb to the top of Nibel
Save at every Spirit Portal
Find 50% of all secrets
Kill 50 enemies with Stomp
Have a close encounter
Restore the winds of Nibel
Clear the haze from the Misty Woods
Kill 500 enemies with Spirit Flame
Trick 5 enemies into killing another enemy
Break open 5 shortcuts using the Charge Flame
Escape a dangerous situation
Cleanse the Ginso Tree's Heart
Cause an enemy to destroy itself
Double Jump 5 times consecutively without touching the ground
Enter the Ginso Tree
Make an unexpected friend
Discover the character in the shadows
Create 50 Soul Links
Restore 50% of all Map Stones
Restore all Map Stones
Collect 200 Energy Shards
Kill 3 enemies without touching the ground
Kill 4 enemies simultaneously using Charge Flame.
Meet the Ancient Being
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
Visit 100% of the map
Earn all Utility Skills in the Ability Tree
Earn all skills in the Ability Tree
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
Crush a Ram with a Stomper
Kill 100 enemies with Charge Flame
Finish the game in under 3 hours
Complete whole game without dying
Complete the whole game without using an Ability Point