The game, which saw moderate commercial success in Japan and received mixed reviews from critics worldwide, was the foundation of Sacnoth's Shadow Hearts series.

Gameplay is divided between event scenes, in which story sequences play; exploration, incorporating puzzle-solving; and a battle screen where players fight monsters spawned in Nemeton.

[1] Exploration is similar to the early Resident Evil games; Koudelka—rendered as a 3D character model—explores environments created with pre-rendered backgrounds shown through fixed camera angles.

Koudelka breaks into Nemeton, losing her magic pendant in the process, and saves wayward adventurer Edward Plunkett from a monster attack.

[8] From visions, human remains and confiscated artefacts, Koudelka learns that Nemeton was a prison for dissidents that now haunt the mansion.

Koudelka discovers a room full of paintings of the destroyed SS Princess Alice and has a vision of Elaine Heyworth, wife of Nemeton's current owner Patrick.

[14] Searching for a way to expand his role, Kikuta was introduced to the chairman of SNK; during their talk, he outlined many perceived pitfalls in the role-playing genre.

[13][14] Although Koudelka used turn-based combat on a grid and random encounters (similar to traditional RPGs), this was not Kikuta's original intention.

He originally planned a real-time battle system with free movement within the environment, combining mechanics from simulation and adventure games.

[17] Kikuta wanted to break away from RPG conventions, but other Sacnoth staff were reluctant to follow his example and retained traditional ideas from Square.

[18] To create an authentic atmosphere, Kikuta used advanced motion capture technology to give realistic physical mannerisms to the character models during real-time cutscenes.

[21] Kikuta's decision to use motion capture, which he called "epoch-making", was part of his attempt to move away from RPG conventions by adding drama.

The motion capture and animation processes were handled by FutureLight and Sacnoth staff, with Kikuta the sessions' executive producer.

[22] According to Kikuta, his research for the narrative and the basic elements of Koudelka took three months;[24] the one-night timescale and singular location were due to the game's limited staff and development time.

His inspirations for the story included Umberto Eco's The Name of the Rose (and its film adaptation), William Hope Hodgson's Carnacki, the Ghost-Finder, H. P. Lovecraft's The Case of Charles Dexter Ward and novels by Lord Dunsany.

[24] Kikuta incorporated a number of historical events and figures, including the sinking of the Princess Alice and fictionalized versions of Lord Dunsany and Roger Bacon.

Nemeton used a blend of architectural styles, with elements ranging from its origins as a Gothic monastery (inspired by St Davids) to contemporary additions.

[26] Koudelka's CGI model was created by Sacnoth and a company founded by artist Nobuji Watanabe, whom Kikuta chose for his passion for good work.

[27] In creating Koudelka's storyline, Kikuta conceived a potential four-part series following her family through the 20th century with events and themes from the original clash of science and magic.

[24][25] Some backstory elements relating to Koudelka were created by Kikuta, such as her meeting a young Jack the Ripper, but not included in the game.

[28] A CD soundtrack album was released in December 1999 by Pony Canyon and Scitron Digital Contents, with over an hour of music and 34 tracks.

[30][31] The album, which included all tracks from the game and live versions of three battle themes (arranged by Naoya Akimoto),[28] received generally-positive reviews from music critics.

[27] The rest of the cast included Gavin Carlton (Ogden), Denise White (Bessy), Scott Larson (James), Rob Brownstein (Alias), Kim Weild (Elaine), Keith Barry (Patrick), and Brian Kojac (Bacon).

A novelization, Koudelka - The Mansion's Scream by Nahoko Korekata, was published by ASCII Media Works in February 2000 as part of its Famitsu Bunko imprint.

[49] An audio drama based on the game, with Japanese actors and excerpts from its score, was released in November 1999 by Scitron Digital Contents.

[2] Alley found the mixture of gameplay styles strange, faulted the game's weapons limitations and praised its innovative take on RPG mechanics.

[2][3][4][54][55] Although Famitsu praised Koudelka's CGI movies and art design, one of its reviewers found some areas too dark to navigate easily.

[3] Chu disliked the in-game graphics, but enjoyed the CGI segments;[4] Both Electronic Gaming Monthly and Power Unlimited also praised the cutscenes.

[52][34] Bratcher cited a lack of atmosphere in general navigation as a negative, alongside the characters' voices not matching their models despite decent quality.

[19] Sacnoth produced two more Shadow Hearts titles (Covenant and From the New World) before it was merged into company owner Aruze in 2007 and ceased video game production.