"Leviathan: The Last Day of the Decade" is a captivating puzzle game that immerses players in a dark fantasy narrative set in a world ravaged by a pandemic. Players take on the role of a detective navigating through a society ruled by five noble families and the ominous Plague King. The game combines storytelling with interactive decision-making, where players must read through the unfolding narrative and make choices that shape their journey.

The gameplay revolves around solving intricate puzzles that are essential for progressing through the storyline. Each decision made by the player can lead to varied outcomes, influencing the moral compass of the character and ultimately resulting in different endings. This element of choice adds depth to the experience, making each playthrough unique as players explore the consequences of their actions in this richly designed world.