Slay the Spire 2 — Mechanics Guide

Instant kill threshold

Stack Doom on enemies. When an enemy's current HP equals or falls below their Doom value, they are instantly killed — regardless of block.

Discard = free play

Cards with the Sly keyword play for free when discarded from your hand during your turn. Enables explosive discard combo turns.

Permanent card modifiers

Enchantments are permanent upgrades applied directly to cards that last the entire run. They add powerful effects but often come with trade-offs.

4-player online

Up to 4 players can tackle the Spire together. Co-op introduces exclusive cards designed for team synergies — share armor, double ally attacks, and more.

Ancient NPC rewards

At the start of each Act, ancient NPCs offer powerful boon choices. Unlike the original game's Neow, boons now appear throughout the entire run.

Companion mechanics

Summon Osty, the Necrobinder's giant reanimated hand. Buff Osty to deal damage and absorb hits. Osty acts independently each turn.

Remove card from combat

Exhausted cards are removed from your hand and deck for the rest of combat. Many Ironclad cards gain bonuses when cards are exhausted.

Passive elemental effects

Channel orbs into slots for passive end-of-turn effects. Lightning deals damage, Frost generates block, Dark stores damage, Plasma generates energy. Focus amplifies all orb effects.