[5] It was one of the first video games to use CD-ROM, which was utilized to provide enhanced graphics, animated cut scenes,[6] a Red Book CD audio soundtrack,[3] and voice acting.

All English translations of Ys II were part of a compilation; no standalone version has been localized (except for iOS and Android ports).

Ys I begins with a cutscene showing the main character, Adol Christin, gazing out to sea at the Stormwall which appeared around the island Esteria six months ago.

Adol then encounters the fortune-teller Sara, who tells him that she had a vision that a fiery-headed swordsman who would play a key role in Esteria's fate.

Sara informs Adol that one book is in the Shrine of Solomon and sends him to the town of Zepik to speak with her aunt Jeba to learn more.

Raba was a scholar visiting Esteria who was inside the Tower of Darm, studying its history, when the demons suddenly appeared.

In addition, Luta is a descendant of the ancient Ys priest Gemma, and Adol is given another amulet with the power to dispel magic seals.

As Adol uses the Monocle to read the entire set of books, a powerful white light fills his vision, and a feeling of serenity overcomes him.

A flashback to 700 years ago is shown: the two Goddesses of Ys are standing around a large glowing orb with their eyes closed, deep in concentration.

Suddenly, a flying pigeon arrives at the clinic bearing a message from the doctor, which states that he has been trapped in the Rasteenie mines by a cave in as he was picking herbs.

They also revealed more about the history of Ys, stating that unknowingly, the source of demons was brought with them when they created the floating island 700 years ago around the Shrine of Solomon.

Adol rescues the boy with the help of a friendly and intelligent demon named Keith, and is allowed to proceed onward from Lava.

Adol meets with an elderly villager, Hadat, whose son, Sada, had recently entered the shrine in an attempt to save his kidnapped fiancée, Maria.

Undaunted, Adol keeps exploring the rest of the Shrine of Solomon, and again encounters the friendly demon Keith, who tells him that Maria is being held for sacrifice in a nearby bell tower called the Campanile of Lane.

Reah explains the events that had led to this point: 700 years ago, after the demons had been defeated, the Goddesses sealed away the power of the Black Pearl, a great orb that was the source of magic in the society of Ancient Ys, as they had discovered the magic from the Black Pearl had caused the creation of demons as a side effect.

The Goddesses also chose to stay behind on the surface of Esteria, and sealed away the magic-enhancing metal Cleria deep in the ground, after which they went into a long slumber.

This released enough magic to enable Dark Fact to break the seal on the Black Pearl, leading to the events of Ys I.

With the descendants of the Priests of Ys and the Goddesses present, Adol is lent their power before he faces his final opponent: the sentient form of the Black Pearl, Darm.

They all congratulate him and note that with the Black Pearl destroyed, the floating island of Ys was slowly sinking back to its original position, in the giant crater on Esteria.

An improved version dubbed Ys I & II Chronicles Plus was released in North America and Europe on February 14, 2013, through Steam and later GOG.com.

The August/September 1990 issue of TurboPlay magazine praised the game in its review, stating that the introduction sequence is "mind-blowing", that "everything, from the graphics to the gameplay, is incredible".

[30] GamePro said it "has got it all", including "great graphics, engaging RPG gameplay, and a brain-draining quest" as well as "stunning" music and "excellent animation sequences".

They compared its storyline to "a best-selling fantasy novel", praised its "outstanding use of voice and real music from the CD", and concluded the "game is magnificent from beginning to end, blowing away all competing RPGs hands-down".

[22] PC Engine Fan, in its 1992 all-time rankings, selected Ys I & II as the third best game of all time, as well as second for best music and sound, fifth for best playability, and third for best difficulty.

It praised various aspects of the game, including the responsive controls, the graphics as having "stood the test of time", the soundtrack as an "audio masterpiece" (giving the sound a 100% score), the "vocal performances" and "dubbing" as surpassing "most gaming dubs produced today", the "fantastical world", and the "story of tragedy, hope and life".

The reviewer Lucas M. Thomas described the "incredibly simplistic gameplay design choice" of "ramming" into enemies as "interestingly addictive" and found that it "streamlines the entire experience, which benefits the progression of the game's plot".

He also praised the soundtrack as "one of the best to be heard" on the Virtual Console and concluded that it is "hard to argue against the value of getting two games' worth of content combined together into one double-length adventure".

[54] The game's early Red Book audio soundtrack was composed by Yuzo Koshiro, Mieko Ishikawa and Hideya Nagata and arranged by Ryo Yonemitsu.

[5] In 1990, TurboPlay magazine wrote that it gets the reviewer's "vote for having the greatest sound and music track ever recorded for a video game".

[30] In Computer Gaming World, reviewer Roe R. Adams (who worked on the Wizardry series) praised the "lush" background music, and speech "heard in real voice, not digitized!