Here is the full list of all 20 Arkham Horror: Mother's Embrace achievements.
Kill the Dark Young with a Birthling explosion.
Have 75 items in your Office Chest at one time
Commit suicide by smoking a cigarette
Use a Bromo Coffee when you Action points are full
Save Arkham from the Dark Young
Find the recipe in every scenario
Completed "A Morbid Dance in the Second Line"
Steal Lanuit's trinket from his store
Kill 3 opponents in a single investigator's turn
Completed "Tendrils of Witchcraft"
Completed "Unwelcomed Guests"
Visit a Outhouse
Completed "The Peculiar Monsieur Lanuit"
Completed "Herd of Algedi"
Heal enemy with a Wild Cast
Use a Radithor on an investigator without any Conditons
Completed "What Was Lost is Never Found"
Completed "Finding Meaning in the Stars"
Completed "An Invitation"
Use the same investigator for every scenario of the game