Here is the full list of all 50 Batbarian: Testament of the Primordials achievements.
Beat the game (Ending C)
Collect 10 iron skin potions
Defeat Cobalt
Have Rowr join the team
Discover the truth
Defeat the pesky ghost for real this time
Defeat the Ogre Leader
Collect 10 Ogre draughts
Find 25 gems
Pip is frozen now...
Defeat the Goddess and her undead servant
Find 10 upgrade satchels
Discover the Ethereal Palace...
Carry 30 stones
Kill the drakin
Pip is on fire
Find 10 gems
Hit that annoying lever
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
Have Drai Lez join the team
Read something in the dungeon
Defeat Drai Lez after his betrayal
Defeat the demon Vorga
Defeat Lamara
Spare the drakin
Get all heart upgrades
Find all the maps
Trick the imps
Bribe your way in twice
Recover the ghost's memory
Save Friffle and his kids
Collect 3 stone fragments
Get Friffle's kid's name right
Beat the game (Ending B)
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
Carefully beat a boss without getting hit
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