Here is the full list of all 23 Costly Adventure achievements.
Miss an attack when the first boss is about to dodge your attack.
Maintain 3 stacks of Curse of Decay on a common enemy for 30 turns.
Deal 500 or more damage with a single character.
Have 13 or more characters burning at the same time during the last boss fight.
Perform a critical strike with 5 characters.
Perform a critical strike with 6 characters.
Perform a critical strike with 7 characters.
Perform a critical strike with 8 characters! Amazing.
Destroy the Molten Shield on the last boss in one turn.
Attack with a character that is entangled in a spider web.
Half or more of the characters on the board have Wild Seed.
There were 10 or more distinct attacks in one turn.
Have a character attack while under an influence of three Auras of Glory.
For two full levels keep the prayer candle burning.
Critical strike with Rogue three times in a row.
Have more than a half of the board be Hunter.
Have no Hunter present on the board.
Win the campaign with the Holy Gemstone specialization.
Win the campaign with the Awakened One specialization.
Win the campaign with the Frenzy specialization.
Only the most determined manage to win the campaign with the Brutality specialization. Well done!
Win the campaign with Frenzy specialization while having at least 21 points in the support tree.