Here is the full list of all 26 So long as there is Mercy achievements.
Get all Achivements
Sacrifice Mercy
Carry all objects to the last room once
Carry all 3 Books form the attic to the final room
Carry the toiletpaper form the bathroom to the final room
Burn all burnable objects in all levels
Burn all burnable objects in the bathroom
Sacrifice Spé
Find your lost brother
Carry the pot from the attic to the final room
Say farewell to the GC
Burn all burnable objects in the attic
Hear every story from the GC
Burn all spiderwebs in every level
Burn all spiderwebs in the kitchen
Meet Kimya
Burn all burnable objects in the kitch
Burn all burnable objects in the base
Burn all spiderwebs in the basement
Meet Jivan
Burn all spiderwebs in the bathroom
Meet Izumi
Burn one object wich is not puzzle relevant
Burn all spiderwebs in the attic
Burn one Spiderweb
Meet Lucien