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