Full list of all 46 Slay the Spire achievements. It takes around 60-80 hours to unlock all of the achievements in the base game on Windows.
The base game contains 26 achievements, and there are 8 DLC packs containing 20 achievements.
Defeat a boss in a single turn.
Have 999 Block during combat.
Play 10 Shivs in a single turn.
Apply 99 or more Poison on a single enemy.
Have 3 or fewer cards in hand, draw, and discard pile combined.
Have 99 or more Block during combat.
Exhaust 20 cards in a single combat.
Defeat a boss without taking any damage.
Win a battle with 1 HP remaining.
Defeated the Time Eater.
Have 10 or more buffs during combat.
Win a combat without playing an Attack.
Have 9 Energy during a single combat.
Beat the game with the Silent.
Defeated Donu & Deca.
Play 25 cards in a single turn.
Defeated the Slime Boss.
Defeat 3 enemies with Poison in a single combat.
Beat the game with the Ironclad.
Defeated the Awakened One.
Defeated the Collector.
Have 50 or more Strength during combat.
Defeated the Bronze Automaton.
Defeated Hexaghost.
Defeated the Champ.
Defeated the Guardian.
Obtain all other Achievements.
Finish Donu with a Feed.
Complete Ascension Level 10.
Beat the game in under 20 minutes.
Beat the game with a single relic.
Beat the game with a 5 card deck or smaller.
Unlock Ascension mode.
Beat the game with a deck of only common cards.
Have 25 or more Focus during combat.
Beat the game with the Defect.
Channel 9 Plasma in a single turn.
Win a Daily Climb.
Defeat the Transient before it fades away.
Complete Ascension Level 20.
Beat the game with the Watcher.
Complete the Ending with the Watcher.