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Spire I Act Music
Gameplay

Spire I Act Music

by GaiusCassiusLonginusv1.1.0

Brings Slay the Spire I Act 1/2/3 themes, Boss battle tracks, and victory music into Slay the Spire II. Choose Random, Disabled, or a fixed theme for each Act, with continuous playback across rooms and adjustable volume.

Created

Aug 10, 2026

Updated

Aug 10, 2026

View on Nexus Mods

Description

# Spire I Act Music

Bring the music flow of Slay the Spire I into Slay the Spire II.

This mod adds the Act themes, Boss battle tracks, and Boss victory music from the first game. Instead of restarting the Act theme every time you return to the map, the selected track continues across the map, normal fights, elites, events, shops, rest sites, and treasure rooms.

## Main Features

- Separate music settings for Acts 1, 2, and 3.
- Choose Disabled, Random, or a specific track for each Act.
- Random choices are stable for the current run and do not reroll after loading a save.
- The selected Act theme continues across normal rooms without restarting.
- Special scripted music is left untouched whenever possible.
- Dedicated Slay the Spire I Boss music for each Act.
- Dedicated Boss victory music for Acts 1, 2, and 3.
- Full support for the Act 3 Double Boss sequence.
- Adjustable replacement volume from 0% to 100%.
- The replacement volume also follows the game's Master and BGM volume settings.
- No changes to cards, relics, enemies, map generation, balance, or save data.

## Act Theme Pools

### Act 1

- Exordium
- Battle Trance

### Act 2

- The City
- Escape Plan
- The City 2

### Act 3

- Dramatic Entrance
- The Beyond

Random mode picks one theme from the selected Act's pool. You can also lock an Act to one specific theme or disable replacement for that Act entirely.

## Boss and Victory Music

- Act 1 Boss: Boss 1, followed by Pass 1 after victory.
- Act 2 Boss: Boss 2, followed by Pass 2 after victory.
- Act 3 Boss: Boss 3 by default, followed by Pass 3 after victory.

For a normal single-Boss Act 3, the settings menu lets you choose either Boss 3 or Boss 4. Boss 3 is the default.

During the Act 3 Double Boss sequence, the first fight uses Boss 3 and the second fight uses Boss 4.

## Requirements

RitsuLib 0.5.4 or newer is required:

https://www.nexusmods.com/slaythespire2/mods/137

## Installation

1. Install RitsuLib 0.5.4 or newer.
2. Download the main file and extract it into the `mods` folder inside your Slay the Spire II installation directory.
3. The final structure should contain `mods/SpireOneActMusic/mod_manifest.json`, `SpireOneActMusic.dll`, and the `assets` folder.
4. Launch the game with mods enabled and make sure both RitsuLib and Spire I Act Music are active.
5. Open the in-game Mod Settings menu to configure each Act and the replacement volume.

## Compatibility

Mod version: 1.1.0

Minimum supported game version: 0.110.0

Tested game version: 0.110.1

This mod only changes music playback. Other mods that replace BGM or patch the same music controller may conflict with it. If you encounter unexpected switching or silence, temporarily disable other music mods and test again.

Slay the Spire II is still being updated. Future game updates may require a mod update. When the custom music controller cannot take over safely, the mod attempts to restore the original game music.

## Bug Reports

Bug reports are welcome. Please include:

- Game version
- RitsuLib version
- Character, Act, and Ascension level
- Selected music mode and track
- Room type where the issue occurred
- Steps to reproduce the issue
- Whether it happens consistently
- The latest `godot.log`

Windows log location:

`%APPDATA%/SlayTheSpire2/logs/godot.log`

## Video

https://www.bilibili.com/video/BV1p9My6WEmQ/

## Credits

Slay the Spire and Slay the Spire II were created by Mega Crit.

The original Slay the Spire soundtrack was composed by Clark Aboud.

This is an unofficial, free fan-made mod and is not affiliated with or endorsed by Mega Crit or Clark Aboud.

Thanks to the RitsuLib developers and to everyone who tested the mod, reported bugs, and suggested improvements.