- Banned in China: Moonstone was banned in Germany because of its content.
- Executive Meddling: Mindscape forced a rush in the development for a 1991 Christmas release. Because of this, the final version contained several bugs and was prone to crashing.
- Follow the Leader: The combat was greatly influenced by Barbarian: The Ultimate Warrior, a classic Commodore 64 game.
- Sampling: Many of the combat sounds were recorded from Red Sonja.
- What Could Have Been: Due to the rushed development, several intended features were left out, including more RPG elements and a save feature.
- Before the game was released, early screenshots showed a fifth knight being playable. Also, the battle in the Valley looked very different from the final version.
- A sequel was planned by Rob Anderson, but it was scrapped pretty quickly because of Moonstone's disappointing sales performance.
Trivia / Moonstone: A Hard Days Knight