Crypt Underworld OST

Crypt Underworld is an experimental FPS video game by Lilith Zone with music by ESPer99. While ESPer99’s Soundcloud features some music (in addition to alternate cuts), it doesn’t feature all the music in the game.

Outside of a few select tracks, most of the ambience is constructed by layering a variety of slowed-down and pitch-shifted stems.

Extracting and Reconstructing Music

The game is made in Unity.

First, I used AssetRipper to extract all assets from the final game.

Second, I opened the scenes to determine which sounds it plays and how. The .scene files are text so I used Notepad to interpret them. I searched for AudioSource objects. This contains the m_audioClip field which specifies the guid of the sound to play. All GUIDs are stored in the *.meta files. Don’t be thrown off by the number of AudioSource objects since every NPC that plays a sound also has one.

Ghost Buffet

The base stem is fallingfalling.wav. There are two layers:

1. 50% speed with Unity’s “Psychotic” reverb preset

2. 25% speed with Unity’s “Psychotic” reverb preset