Here is the full list of all 21 Snowflake's Chance achievements.
Make it past the first tier.
Be a jerk to your scampering comrade.
You should have seen that one coming...
Discover a secret alcove.
Reach the underground forest.
Survive the void.
Reach the Elephant Bridge without dying.
Befriend three Ghost Butterflies at once.
Escape the lord of the Pit.
Walk the earth again.
End the nightmare.
End the nightmare with 25 Baubles.
Be nice.
End the nightmare without dying.
Sit on the Pit Lord's throne.
Earn back 3 chances.
Have attack, jump and health upgraded at the same time.
Fly too high.
Have 3 different critters at the same time.
Find a whacking stick.
End the nightmare on Brutal Mode.