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