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