Eternal Darkness: Sanity's Requiem may appeal to fans of survival horror. The game offers old school gameplay. In it you need to explore locations, solve riddles, collect items, save resources, fight monsters or run away from them. The project stands out for its large number of playable characters. Switching between them occurs strictly according to the plot. The second feature is the morality indicator. If it resets to zero, the hero or heroine will begin to see hallucinations. These are called madness effects here. Among them there are endless corridors, corpses appearing, limbs falling off and other phenomena. There are also some very unusual things. For example: the game can simulate deleting a save, lock controls, change the volume, pause the progress.

The title of the project is translated into Russian as Eternal Darkness: Requiem for Sanity. The plot spans many centuries. History is constantly transferred from the present to the past, and vice versa. The video game gives you the opportunity to control 12 characters from different eras – from a Roman centurion to a collector from the 1980s. Among the heroes there is also a priest from the times of the Inquisition, a hunter and other protagonists. Each of them has its own storyline. The overall narrative follows Alexandra Roivas' attempts to investigate the murder of her grandfather Edward. In the mansion of a relative, the heroine finds the Tome of Eternal Darkness. This book is made of human flesh and skin. When a girl reads it, she seems to be transported to bygone times and experiences the events described in reality. Returning to her reality, the American woman finds other tomes in the house and plunges into new, alien memories.