Here is the full list of all 50 Batbarian: Testament of the Primordials achievements.
Beat the game (Ending B)
Defeat Lamara
Defeat the demon Vorga
Defeat Drai Lez after his betrayal
Collect 3 stone fragments
Collect 10 iron skin potions
Collect 10 Ogre draughts
Have Rowr join the team
Find 10 upgrade satchels
Discover the truth
Defeat the pesky ghost for real this time
Defeat the Ogre Leader
Find 25 gems
Bribe your way in twice
Hit that annoying lever
Pip is frozen now...
Defeat the Goddess and her undead servant
Discover the Ethereal Palace...
Carry 30 stones
Kill the drakin
Pip is on fire
Find 10 gems
Trust Twigs to join your team
Defeat the three headed lich in the ruins
Get the dash boots and the power ring
Oops. A short lived companionship.
Defeat the quivering ancient
Carefully beat a boss without getting hit
Have Drai Lez join the team
Read something in the dungeon
Defeat Cobalt
Spare the drakin
Get all heart upgrades
Find all the maps
Trick the imps
Recover the ghost's memory
Save Friffle and his kids
Get Friffle's kid's name right
Beat the game (Ending C)
Beat the game (Ending A)
Have Pip do an elemental strike on an enemy weak to it
Reach the ogre fortress factory's entrance without being caught once.
Never miss a chance to say you hate magic
Find all gems
Collect 10 awareness potions
Unlock all bestiary entries
Loot 100% of the chests
Reach the final boss and escape the cave victorious in under 3 hours
Reach the final boss and escape the cave victorious without dying
Complete the puzzle piece and arena goblet trophies in Forgotten Roots