Here is the full list of all 8 Asphyxia achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
De Quincey confides in Samantha.
Samantha attempts to sleep, but cannot.
Roberta tells a chilling horror story.
Samantha succumbs to despair.
Samantha and Lillian make a tentative truce.
Lillian remembers her childhood - the good and the bad.
Samantha attempts to escape from herself.
Samantha reflects on her feelings for Lillian.