Here is the full list of all 30 Feral Fury achievements.
Complete Stage 5 with Admiral Pawgarr
Complete Normal Mode
Complete Stage 4 on Hard difficulty
Return the Missing Book
Close 10 Wishing Wells
Squash 20 lizards
Complete an Entire Stage Without Taking Damage on Normal or Hard Difficulty
Use 9 Syringe Rooms
Rob a store
Unlock 10 Upgrades
Spend 30 Coins on Vending Machines
Send 10 Marines into Battle
Complete Stage 2 on Normal difficulty
Complete Stage 1 on Normal difficulty
Go Through a Teleporter
Complete Easy Mode
Complete Stage 3 on Normal difficulty
Complete Stage 5 with a Panda Marine
Complete Stage 5 with Rose the Red
Complete Stage 5 with The Traitor
Defeat The Corrupted with a Panda Marine
Defeat The Corrupted with Admiral Pawgarr
Defeat The Corrupted with Rose the Red
Defeat The Corrupted with The Traitor
Unlock all Secret Doors
Open the Talismans Portal
Get 150 000 points in a Daily Run
Complete Curse Mode
Complete Feral Fighters with at least 9000 points