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