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 Slime Boss.
Defeated Hexaghost.
Have 3 or fewer cards in hand, draw, and discard pile combined.
Win a battle with 1 HP remaining.
Win a combat without playing an Attack.
Exhaust 20 cards in a single combat.
Have 9 Energy during a single combat.
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.
Play 10 Shivs in a single turn.
Play 25 cards in a single turn.
Defeat a boss in a single turn.
Defeat a boss without taking any damage.
Defeated the Guardian.
Defeated the Bronze Automaton.
Defeated the Collector.
Defeated the Champ.
Defeated the Awakened One.
Defeated Donu & Deca.
Defeated the Time Eater.
Beat the game with the Ironclad.
Beat the game with the Silent.
Obtain all other Achievements.
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.
Unlock Ascension mode.
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.
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.