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