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