Eternal Darkness

The game is conducted from a third-person perspective. It has an in-game map which tracks the player's bearings. The inventory system stores weapons and items that can be used to solve puzzles, some of which can be combined with other objects, even enchanted with magick, for different effects.

Combat focuses on a simple targeting system. Players may attack in a general direction, or lock-on to an enemy to focus on individual parts of its anatomy. Decapitating most enemies effectively blinds them. There are many classes of enemies the player must either defeat or avoid.

The story of Eternal Darkness takes place over four fictional locations which the game moves between. They include the "Forbidden City" underground temple complex in Persia; a Khmer temple in Angkor Thom, Cambodia; Oublié Cathedral in Amiens, France; and the Roivas Family Estate in Rhode Island, which leads to an ancient underground city named Ehn'gha beneath the mansion. The story moves between these locations, with each chapter occurring during a different time period (between 26 B.C. and 2000 A.D.), and from the perspective of a different character. The chapters in the game are not in chronological order.

In 2000 AD, Alexandra Roivas returns to her family's estate in Rhode Island after her grandfather, Edward Roivas, her only living relative, is found brutally murdered. Two weeks later, the local police have gotten nowhere with the investigation. Alex decides to investigate the mansion for clues, and stumbles upon a secret room containing a book bound with human skin called the Tome of Eternal Darkness. Deciding to read it, she finds it contains accounts of various people in the past, beginning with the story of Pious Augustus in 26 BC.

Eternal Darkness was developed by Canadian development studio Silicon Knights and published by Japanese game company Nintendo. It was directed and produced by Denis Dyack of Silicon Knights. The project's origins can be traced back to the mid-1990s when Nintendo staff saw Silicon Knights' game Blood Omen: Legacy of Kain (1996) at an E3 gaming convention. Nintendo contacted Silicon Knights, as they had been contemplating adding more mature games to their line-up, and the two companies began collaborating to produce Eternal Darkness.

Silicon Knights's concept for the game was to create a horror game that did not fall under the survival horror genre. Dyack claims they went with "a deeper, more classical approach" to horror, calling it a "psychological thriller" as opposed to the "B-movie horror plots" of the Resident Evil series. They also wanted to make a game in response to contemporary video game controversies. Dyack explains: "Video games were under fire for messing with people's heads, and being accused of being murder simulators and stuff.

Eternal Darkness: Sanity's Requiem received critical acclaim upon its release, with aggregated review scores of over 9/10 at both GameRankings and Metacritic. Upon review, IGN gave Eternal Darkness one of its Editor's Choice Awards and, in its review of the game, stated: "Simply put, an amazing achievement that shouldn't be overlooked. Games do not come any better than this".

The game was reviewed for the Japanese magazine Famitsu Cube + Advance . The four reviewers all complimented the story as engaging, with one reviewer specifically found it engaging how the stories and characters gardually weave themselves together. One reviewer said the combat scenes were somewhat repetitive while another said that running in the game was awkward. While all reviewers said the game was strictly for adults, one said that this would limit the game's audience.

Alex Roivas makes a cameo appearance in the 2018 fighting game Super Smash Bros. Ultimate as one of the many "Spirits" that players can collect. The battle associated with Alex's Spirit sees the player needing to defeat Zero Suit Samus from the Metroid series while the screen is mirrored at random intervals. The patent for the sanity system expired in 2021.

In 2006, Dyack said "absolutely yes" in response to the question of a possible sequel. He stated that Silicon Knights had intended for Eternal Darkness to be a stand-alone game, but they wanted to make more games set in the same universe involving the Ancients. At Microsoft's Spring 2008 Showcase, Dyack said there was a "strong chance" they would return to the Eternal Darkness brand. In 2011, Silicon Knights said they were refocusing on one of their most requested titles for the next generation of consoles.