Slay the Spire 2 does not just bring back the three-act structure from the original; it doubles it. Each act now comes in two distinct variants, giving every run a genuinely different feel from the last. Here is a full breakdown of how the act system works and what is available right now in Early Access.
Slay the Spire 2 at a Glance
| Detail | Information |
| Release Date | March 5, 2026 (Steam Early Access) |
| Developer / Publisher | Mega Crit |
| Price | $24.99 |
| Platform | PC via Steam (Windows, macOS, Linux) |
| Console Release | Planned for 2027 after full release (PS5, Xbox, Switch 2) |
| Early Access Duration | Estimated 1 to 2 years |
| Total Acts (Full Game) | 6 (3 base acts, each with 2 variants) |
| Acts Playable Now | Act 1a, Act 1b, Act 2a, Act 3a |
You can purchase Slay the Spire 2 via Steam for $24.99.
How Many Acts Does Slay the Spire 2 Have?
Slay the Spire 2 features 6 acts in total, built around a system where each of the three original acts now has two alternate variants. At the start of each act, the game randomly selects one of the two available environments for that act, meaning no two runs will follow the exact same path.
However, not all six acts are available yet. Early Access currently includes Act 1a, Act 1b, and the first variants of Acts 2 and 3. The alternate “B” variants for Acts 2 and 3 are confirmed to arrive during Early Access, though exact release dates have not been announced by Mega Crit.
| Act | Name | Status |
| Act 1a | Overgrowth | Available now |
| Act 1b | Underdocks | Available now |
| Act 2a | Currently Unnamed | Available now |
| Act 2b | Currently Unnamed | Release date TBD (during Early Access) |
| Act 3a | Currently Unnamed | Available now |
| Act 3b | Currently Unnamed | Release date TBD (during Early Access) |
How the Act System Works?
The structure within each act stays true to what fans know from the original Slay the Spire. You choose your route on a branching map, deciding which encounters to take on and which to avoid. At the end of every act, a boss awaits. Defeating the boss restores your full HP and rewards you with one of three powerful upgrades to carry into the next act.
What makes the new system different is that each act now has its own pool of enemies, Events, and Bosses tied to its specific environment. So Act 1a (Overgrowth) and Act 1b (Underdocks) are not just visual reskins — they each bring a distinct set of encounters that require different approaches. Each act also comes with at least three boss options, with Mega Crit potentially adding more as Early Access develops.
A standard run completing all three acts takes roughly one to two hours, depending on whether you play solo or in co-op with up to four players.
Playable Characters in Early Access
Slay the Spire 2 launches with 5 playable characters, made up of 3 returning from the original game and 2 brand-new additions. Each character brings unique cards, mechanics, and starting relics. You select your character at the start of each run, and in co-op mode you can mix and match characters across the team.
| Character | Type | Key Mechanics | Notes |
| Ironclad | Returning | Strength scaling, Bash and Strike focus, Exhaust synergies | Classic melee tank with updated cards designed for the multi-act structure |
| Silent | Returning | Poison, Shiv, Discard, Lethal, and Artifacts | Stealthy control playstyle; new Events in Act 1b favour poison builds |
| Defect | Returning | Orbs (updated with larger body and a teased 4th orb), Channel and Focus | Tech and plasma builds; orb mechanics tweaked for alternate act encounters |
| Necrobinder | New | Doom (a Poison-like damage-over-time that resolves at end of turn), Souls (generates extra draws), and Osty (a skeletal left hand that can be sacrificed for damage or Block and then revived) | Starts at 35 HP; lich-themed playstyle built around binding corpses; strong synergy with Underdocks |
| Regent | New | Stars (build and consume alongside mana to generate cards), Forge (upgrades a signature weapon over the course of a combat), and Minions (transforms cards into loyal fighters) | Alien heir character with Throne of Stars lore; cosmic theme fits well with Overgrowth |
The Watcher (returning from Slay the Spire 1 with her Wrath, Calm, and Divinity stance mechanics) is confirmed for Slay the Spire 2 but unlocks after the current Early Access build. Mega Crit has also teased at least one additional mystery character for the full release.
Act 1a: Overgrowth
Overgrowth is the first of the two Act 1 variants currently available in Slay the Spire 2. It carries its own enemy pool, Events, and boss encounters, and represents the more familiar starting environment for players coming from the original game. The Regent’s cosmic theme fits naturally into Overgrowth’s environment.
Act 1b: Underdocks
Underdocks is the alternate Act 1 variant and introduces a completely different environmental setting with its own unique enemies and Events. Because the game randomly assigns one of the two Act 1 variants at the start of each run, you will not always know which one you are getting until you begin climbing. The Necrobinder’s lich-themed mechanics have a natural synergy with the Underdocks environment.
Acts 2b and 3b: Coming During Early Access
The alternate variants for Acts 2 and 3 are confirmed for release during the Early Access period, but Mega Crit has not announced specific launch dates for either. Both are listed as “coming soon” in the current build, and Mega Crit is actively collecting in-game feedback to shape how the remaining content develops.
Early Access Roadmap
Mega Crit is planning a 1 to 2 year Early Access period focused on polish, balance, and feedback-driven additions. Based on the current build and Mega Crit’s launch communications, here is how the roadmap breaks down:
| Phase | Content | Estimated Timeline |
| Now (v0.98.1) | Acts 1a, 1b, 2a, and 3a; 5 characters; Epoch unlocks; 4-player co-op | Live from March 5, 2026 |
| Mid Early Access | Acts 2b and 3b with unique enemies, bosses, and Events; additional bosses per act; Watcher character | Community estimate Q2 to Q3 2026; listed as “coming soon” in the current build |
| Late Early Access | Full 6-act experience; Steam Achievements; narrative ending; final balance pass | Targeting 2027 full release, then console ports |
| Ongoing | Hotfixes (v0.98.1 already addressed language-related crash-to-desktop issues); Steam community feedback continues to shape act variants | Continuous |
Note: Mega Crit has not confirmed hard dates for any of the above milestones. The timeline above reflects community estimates and Mega Crit’s own Neowsletter communications. Based on how Mega Crit handled Slay the Spire 1’s Early Access, rapid and consistent updates are expected throughout.
What Changes Between Acts
Beyond the environment and enemy pools, each act transition in Slay the Spire 2 brings additional systems that were not present in the original game.
- New boon-givers appear at the start of each act. Neow remains the starting boon-giver, however, new characters such as Tezcatara take over from Act 2 onward, offering their own upgrade bargains.
- Completing acts feeds into the Epoch system, which is Slay the Spire 2’s meta-progression framework. Each Epoch represents a lore drop tied to the Spire’s history and unlocks new content including neutral cards, relics, and new biomes for future runs.
- Ascension modifiers stack across acts. Every time you clear Act 3, you unlock a new Ascension level. These modifiers affect all future runs by adding difficulty, such as spawning more Elite enemy encounters.
Alternate Acts and Replayability
The Alternate Acts system is one of the biggest structural changes in Slay the Spire 2, and it directly addresses one of the main criticisms of the original: that experienced players could eventually predict and autopilot through the map. With two possible versions of each act in the rotation, every run now has a genuinely different shape, and the randomised assignment means you need to stay adaptable regardless of how many hours you have logged.
| Feature | Original Slay the Spire | Slay the Spire 2 |
| Total Acts | 3 | 6 (3 base acts x 2 variants each) |
| Act Variants | None | 2 per act |
| Playable Characters | 4 | 5 at Early Access launch |
| Boss Pool per Act | Multiple | Multiple (at least 3 confirmed) |
| Meta Progression | Unlock system | Epoch system with lore drops |
| Boon-givers | Neow only | Neow + new characters per act |
| Ascension | Available | Available, stacking modifiers |
What Is Still Missing in Early Access
Slay the Spire 2 is open about what is not finished yet, and Mega Crit has been transparent about the roadmap. Here is what to keep in mind before climbing:
- Acts 2b and 3b are not yet available and have no confirmed release dates.
- Steam Achievements are disabled until the full content count is finalised.
- No true narrative ending is in the current build.
- The Watcher (returning from Slay the Spire 1 with her Wrath, Calm, and Divinity stance mechanics) is confirmed for Slay the Spire 2 but is not yet available in the current Early Access build. She is expected to arrive during the mid Early Access phase.
- At least one additional mystery character has been teased by Mega Crit for the full release.
- Console versions for PS5, Xbox, and Nintendo Switch 2 are planned for 2027 following the full PC release.
- Balance changes are actively ongoing, so card values and encounter difficulty will shift across updates.
- Placeholder art and icons appear in some sections of the current build, most notably in the Epoch unlock screen. These are expected to be replaced as development continues.
Quick Summary
- Slay the Spire 2 has 6 total acts across three base acts, each with two alternate variants.
- Act 1a (Overgrowth) and Act 1b (Underdocks) are both available now, along with Act 2a and Act 3a.
- Acts 2b and 3b are coming during Early Access with no confirmed dates yet.
- The game launches with 5 playable characters: Ironclad, Silent, Defect, Necrobinder, and the Regent.
- Each act variant carries its own unique enemies, Events, and Boss pool.
- Completing acts feeds into the Epoch meta-progression system and unlocks new content for future runs.
- A full three-act run takes roughly one to two hours in both solo and co-op play.
- Mega Crit is targeting a 1 to 2 year Early Access window before the full 1.0 release.
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