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