Here is the full list of all 30 Caverns of the Snow Witch achievements.
Steal a meal of duck
Find the ultimate ending in Free Read mode
Fly on a Pegasus
Successfully navigate your way past the Banshee
Deny the Brain Slayer of a meal
Remember an old legend to your benefit
Survive being swept up by an avalanche
Steal a boat and sail away
Convince the centaurs that you have nothing of value
Beat the Snow Witch at her own game
Slay the zombie replicas of your friends
Experience a particularly nasty shower
Find all three metal shapes
Survive your own murderous hand
Read the spell on the scroll before it fades away
Take all of the Snow Witch's treasure
The Snow Witch is Dead!
Shatter the Crystal Warrior into pieces
Hit the true Illusionist on your first try
Receive a curse from a stranded Dwarf
Try all three of the rings
...even if it's not your birthday
Consume ten of your Provisions
Find the ultimate ending in Hardcore mode
Find the ultimate ending in Medium mode
Find all the images hidden within Caverns of the Snow Witch
Trick two foolish Goblins
Be healed by the minstrel's music
Solve the riddle of the rhyme
Find all enemies with these words in their name