Here is the full list of all 16 Face It - there are A game to fight inner demons achievements.
Unlock any level from darkest world.
Complete World 1
Complete World 2
Complete World 3
Complete World 4
Complete any level without taking any damage.
Complete Lux in Tenebris without taking any damage.
Complete any level from darkest world.
Complete a level with only one point of light remaining.
Unlock the Fight Sigil.
Unlock the Passion Sigil.
Unlock the Will Sigil.
Unlock the Love Sigil.
Unlock the Truth Sigil.
Unlock the Vision Sigil.
Unlock the Reconnection Sigil.