Here is the full list of all 18 The Charnel House Trilogy achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
You recounted Lydia's story perfectly.
You found out the truth about Gavin.
You saved Carli.
Smoking really IS hazardous.
You pulled out an old trick.
You scared off your stalker... for now.
You made Carli mad.
You accepted Floyd's gift.
Should've got a ring with it.
You tried to save Don from boredom... but failed.
You endured Floyd's torment.
You met the master.
She's a stubborn old gal.
You saved Lang from boredom.
You suffered a great loss.
You discovered Alex's identity crisis.
You logged in and tracked your parcel.
You discovered the autobiographical element.