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