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