Here is the full list of all 25 Elden: Path of the Forgotten achievements.
Death finds us all
You killed the first boss
You killed the second boss
You killed the third boss
Learnt Magic
Died to a bat
Discovered failed clone
Completed Forest without dodge roll
Completed game without magic
Learn all magic
Discovered Spear
Discovered Axe
Get poisoned
Completed game with the sword
x10 kills with sword
x50 kills with sword
x10 kills with axe
x50 kills with axe
x10 kills with Spear
x50 Kills with spear
x10 kills with Magic
x50 kills with Magic
Watch the credits
Cure poison effect
A worlds end?