Anyone who buys the game early will get a mini soundtrack CD full of unreleased, early experimental PCM and FM tracks as well as a full version of the opening. The list of tracks is as follows:

1. Dungeon (PCM Experimental Version)
2. Battle (PCM Experimental Version)
3. Emerald Labyrinth (FM Source)
4. Dungeon (FM Source)
5. Battle (Unused FM 1)
6. Battle (Unused FM 2)
7. Opening (Full Version)

Source:
• Dengeki

Related Links:
• Official Site (JP)
• Sekaiju no Meikyuu - Quests, Missions and Services
• Sekaiju no Meikyuu is Receiving an English Release!