Slay the Spire 2 Acts Guide

Slay the Spire 2 has 4 acts, each with unique enemies, bosses, and challenges. This guide covers what to expect in each act and how to prepare for them.

Quick Answer

Slay the Spire 2 has 4 acts. Acts 1-3 are required to beat the game. Act 4 is an optional endgame challenge that requires collecting 3 keys during Acts 1-3 to unlock.

Act 1

— The Exordium

Floors

~15 floors

Difficulty

Easy

Focus

Build your deck foundation

Elites

Gremlin NobLagavulinSentries

Bosses

Slime BossGuardianHexaghost

Strategy Tips

▸Prioritize damage cards early — you need to kill enemies before they scale

▸Take at least 1-2 AoE cards for multi-enemy hallway fights

▸Upgrade your best attack or skill at the first Rest Site

▸Don't skip Elites — you need relics to scale into Act 2

Act 2

— The City

Floors

~15 floors

Difficulty

Medium-Hard

Focus

Refine your deck

Elites

Book of StabbingSpheric GuardianTaskmaster

Bosses

Bronze AutomatonChampCollector

Strategy Tips

▸Act 2 Elites hit HARD — make sure you have enough block generation

▸Remove Strikes and Defends at shops if you have Gold

▸Path through at least 1-2 Rest Sites to heal and upgrade

▸If you're low on HP, prioritize Rest Sites over Elites

Act 3

— The Beyond

Floors

~15 floors

Difficulty

Hard

Focus

Finalize your build

Elites

Giant HeadNemesisReptomancer

Bosses

Awakened OneTime EaterDonu & Deca

Strategy Tips

▸Act 3 enemies punish specific strategies (e.g., Time Eater punishes fast decks)

▸Know your boss before the fight — check the map to see which boss you're facing

▸Upgrade your most important cards at Rest Sites

▸Don't take new cards unless they're S-tier — your deck should be complete

Act 4

— The Heart

Floors

~5 floors

Difficulty

Very Hard

Focus

Optional endgame challenge

Elites

Shield & SpearTransient

Bosses

The Heart

Strategy Tips

▸Act 4 is OPTIONAL — you need to collect 3 keys during Acts 1-3 to unlock it

▸The Heart has 750+ HP and hits for massive damage — your deck must be optimized

▸Bring scaling damage (Strength, Poison, Orbs) — burst damage alone won't work

▸Bring consistent block generation — The Heart attacks every turn

Act Progression

1️⃣

Act 1 — Build Foundation

Take strong cards, fight Elites for relics, upgrade key cards

2️⃣

Act 2 — Refine Deck

Remove weak cards, add synergies, survive brutal Elites

3️⃣

Act 3 — Finalize Build

Deck should be complete, focus on execution and boss prep

4️⃣

Act 4 — Ultimate Challenge (Optional)

Requires 3 keys, face The Heart with 750+ HP

Frequently Asked Questions

How many acts are in Slay the Spire 2?

There are 4 acts in Slay the Spire 2: Act 1 (The Exordium), Act 2 (The City), Act 3 (The Beyond), and Act 4 (The Heart). Act 4 is optional and requires collecting 3 keys during Acts 1-3 to unlock.

Is Act 4 required to beat the game?

No. Act 4 is an optional endgame challenge. You can beat the game by defeating the Act 3 boss. Act 4 is only for players who want the ultimate challenge.

How do I unlock Act 4?

To unlock Act 4, you must collect 3 keys during Acts 1-3: Ruby Key (burn a card at a Rest Site), Emerald Key (take the cursed chest event), and Sapphire Key (defeat an Elite with a special relic). Once you have all 3 keys, Act 4 unlocks after the Act 3 boss.

Which act is the hardest?

Act 2 is generally considered the hardest for most players. Act 2 Elites (especially Book of Stabbing and Spheric Guardian) hit extremely hard, and many runs fail here. Act 4 is technically harder, but it's optional and only attempted by experienced players.

How long does each act take?

Each act takes about 15-20 minutes on average. A full run (Acts 1-3) takes 45-60 minutes. If you include Act 4, expect 60-75 minutes total.

Can I go back to previous acts?

No. Once you complete an act and defeat the boss, you move to the next act. There's no way to go back.