However, it was released in very limited quantities only in France, Italy, and Spain and as such European copies of the game are rare and the very existence of the PAL version remained widely unnoticed.

Depending on the abilities of the Reyvateils in the party, various spells can also be cast to light candles, remove obstacles, and trigger switches.

Once enough battles have been fought to empty the gauge, no further random encounters will take place until the player leaves and returns to the area.

Harmocrystals are activated when the Reyvateil and the rest of the party work well together, a measure of which is represented by the Harmonics bar at the bottom of the screen.

Both kinds of magic become progressively stronger as the Reyvateil continues to sing the same Song, and power up faster with each incremental level of Harmonics.

The Diving experience shares many similarities with Japanese visual novels, which puts great emphasis on dialogue and character development.

In order to enter deeper levels of the Cosmosphere, the player must improve their relationship with the Reyvateil by gaining Dive Points from combat and having conversations with her while resting at inns and camps.

Ar tonelico takes place in the world of Sol Ciel (ソル・シエール), which literally translates to "Sun Sky" in Latin and French, respectively, but means "Shining Sky/World" in the game's own language.

The Tower exists at the center of the world and is made from technology that was available prior to the world-destroying catastrophe known as the Grathnode Inferia.

The Tower functions much like a computer program, and is susceptible to viruses which are emerging at an alarming rate to wreak havoc on both the upper and lower worlds.

Due to the strain that the power of Ar tonelico puts on their bodies, they tend to have naturally short life spans of only 14 to 20 years.

[6] There is a life-extending agent called Diquility that can only be produced by the Church of Elemia (エル・エレミア教会, Eru Eremia-kyoukai) and the Tenba Conglomerate (天覇, Tenpa), but it must be applied every 3 months, and the cost of obtaining it is prohibitive.

The main protagonist is Lyner Barsett, a Knight of Elemia who fell from Platina when attempting to destroy one of the viruses, who was then saved by a reyvateil, Aurica Nestmile.

These two become very important characters, and the player must interact with them on a regular basis by conversing and Diving in order to progress through the game.

Haruka Shimotsuki, Takashige Inagaki and Akiko Shikata also contributed composition for several of the songs and Hymns in the game.

As well as the choral Hymns, the soundtrack features a variety of musical genres ranging from rock, electronica, industrial and rap to ethnic, acoustic, orchestral and folk styles.

Each Reyvateil has their own singer (who is different from their voice actor in both Japanese and English versions) who performed their Songs and Hymns: "Aurica": Haruka Shimotsuki, "Misha": Akiko Shikata, "Shurelia": Noriko Mitose and "Claire": Yūko Ishibashi.

[citation needed] The music of the game was released across three albums: a 2-disc original soundtrack and two Hymmnos Concert CDs.

[citation needed] Hymmnos is a language from the time before the two catastrophes that destroyed the world, and it is used by the Reyvateils to transmit their feelings to the tower to process them into Song Magic, although humans also utilize it for authentication purposes, issuing predefined commands to the Tower and the Download of Hymn Crystals.