Touhou Mahoujou: Book of Star Mythology is an engaging action game that takes players on a journey through the Touhou Project universe. Initially conceived as a music album, it has evolved into a full-fledged game where players collect star items from defeated enemies. The gameplay mechanics emphasize close-range attacks to maximize star item collection, which directly influences the Magnitude gauge and enhances point multipliers. Additionally, gathering sufficient star items can trigger unique boss mechanics, adding depth to the gameplay experience.

The game features a chapter system reminiscent of Legacy of Lunatic Kingdom and offers two distinct modes: 'Legendary Hero Mode' with infinite lives and the traditional 'Legacy Mode'. In Legendary Hero Mode, players respawn at their last location or at the bottom of the screen, providing a more forgiving gameplay experience. This flexibility allows players to enjoy the game at their own pace while still facing the challenges posed by various stages and bosses.