Eternal Blue expanded the story and gameplay of its predecessor, and made more use of the Sega CD's hardware, including more detailed graphics, longer, more elaborate animated cutscenes, and more extensive use of voice acting.

During their journey across the world of Lunar, Hiro and Lucia are joined by an ever-expanding cast of supporting characters, including some from its predecessor.

[2] Lunar: Eternal Blue is a traditional role-playing video game featuring two-dimensional character sprites and backgrounds.

The game is presented from a top-down perspective with players moving the characters across numerous fantasy environments while completing story-based scenarios and battling enemy monsters.

Basic game function remains similar to Lunar: The Silver Star, with story segments being presented as both on-screen text and animated cutscenes.

While the cast's primary personalities remained intact for the English release, some changes such as colorful language, jokes, and double entendres were added to their speech to make the game more comical.

Primary supporting characters include the servants of the Goddess Althena, the creator of Lunar thought to have vanished centuries ago who suddenly appeared in mortal form to lead her people.

They train to fight Zophar, and Ghaleon appears, giving Hiro his sword and explaining his apparent villainy was a ruse to atone for past actions.

According to scenario writer Kei Shigema, the game's concept of an oppressive god came from the image of Sun Wukong, hero of the Chinese epic Journey to the West, being unable to escape from the gigantic palm of the Buddha.

[11] The game's North American version was translated and published by Working Designs, who had previously produced the English release of The Silver Star.

Headed by company president Victor Ireland, the game's script contains the same light humor of the original, with references to American pop culture, word play, and breaking of the fourth wall not seen in the Japanese version.

[9] Like The Silver Star, the North American version of Eternal Blue featured an embossed instruction manual cover.

[15] While the original game's music represented a number of styles and genres, Iwadare purposefully narrowed his range of composition to give the songs a unified feel.

[15] The English version contains an original title not found in the Japanese release, named the "Star Dragon Theme".

While The Silver Star contained only fifteen minutes of voiced content, Eternal Blue features over an hour and a half of pre-recorded speech.

John Truitt also reprises his role as Ghaleon, and is joined by a number of new cast members to the Lunar series, many of which would return in future games.

[20] When the game was released the following December, it was packaged with an 8 cm music disc called the Lunar: Eternal Blue Premium CD featuring short conversations by Lucia and Lemina, as well as in-character theme songs.

[13] Its English release met with a favorable response, with GamePro remarking that "Eternal Blue could appear to some as 'just another RPG,' but the epic scope, appealing characters, and excellent cinematics make it much more," yet found the game's linear story progression to be its low point.

When the editors reviewed the final version, however, they questioned the game's frequent use of jokes and lewd quips in place of the original Japanese narrative[27] which Ireland described as "a complete about-face".

[40] This version would be released in North America in 2000 once again by Working Designs in the form of an elaborate collector's edition package that includes a soundtrack CD, "making of" bonus disc, game map, and a special omake box complete with Eternal Blue collectibles.

"[44] Samuel Bass reviewed the PlayStation version for Next Generation, stating that it is "not one for the technologically fixated, but a brilliant, timelessly charming RPG nonetheless".