Here is the full list of all 18 Blackwell Epiphany achievements.
Somebody's got to do it...
Create no more than 450 footprints
Learn a long kept secret
The hows and whys of Joey
Finish the game in commentary mode (from the first screen till the last)
Complete the story
Try to lie your way out of it
Free yourself
Blow on everyone you can find
Two becomes one
Make a leap without falling once
Reunite a family
Find a secret room
Keep clam and keep cool
She has plenty of time...
Gain access to an online game
Save your first ghost
Solve a puzzle together