Here is the full list of all 26 Othercide achievements.
Activate all Remembrances
Defeat every boss in a single recollection
Discover all story chapters
Defeat The Deacon
Defeat The Child
A Scythedancer has been germinated
Have a level 15 Daughter
Defeat Suffering
Spend 4000 vitae
Kill 300 enemies
Defeat The Maid
Sacrifice a Daughter with one memory attached
Save a Bright Soul
Sacrifice a Bright Soul
Close 20 Synapses
Resurrect one Daughter
Lose 400 HP because of reaction or interruption skills
Start a new Recollection
A Daughter is killed in battle
Sacrifice a Daughter
Earn 5 traits on the same Daughter
Defeat The Surgeon
Add one memory to a Daughter
Close the first Synapse
Finish the tutorial by defeating all enemies
Reach the chrono map