Here is the full list of all 21 Black River achievements.
Be the meal of their party.
Just stare at it.
Get caught by Bobby.
Meet the Crawler.
Thorne is here!
Use him to open the gate.
Get Ira and Bardra to work together.
Find Leah at the Mansion.
Meet the Deformity.
Defeat Blondie.
Witness Calisto breaking the last seal.
Summon Hallvorn.
Release Thorne from his enslavement.
Exit the village alive.
Open the Treasure Chest while being chased by Bobby.
Collect all of Ivy's diary pages.
Rescue all survivors at the Bone Pit.
Get ambushed by the Deformity.
Kick his ass.
Save the villager from the zombies.
Save Matthias from the zombies.