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