Differences
 Legends is unable to make use of the Dreamcast's external hardware, such as the 
rumble pack and 
VMU, to let players know when many treasures or events were near. For example, in the Dreamcast version the official 
Sega  VMU would start to beep whenever there was a Cham in the area. Cupil  would also appear on the VMU screen to guide players to the Cham's exact  location. Since the GameCube version has no VMU, Cupil would instead  start making a "Pyu!" sound and appear in the corner of the screen as an  icon when the player was on top of a Cham. Finally, the rate of random  encounters is slightly lower in the GameCube version but experience  points earned are higher per battle to make up for this.
 There are not many significant graphical differences between the two versions; even the texture 
level of detail bias remains the same despite the GameCube's more powerful texturing abilities. However the 
GameCube  does make use of its improved hardware to reduce saving and loading  times. The majority of character models have gained some additional  polygon counts. In addition, the GameCube version does not require the  use of a second disc, whereas the Dreamcast version does. However, in  order to fit on the single GameCube disc, the music in 
Legends is of a lower quality than the Dreamcast version.
 
Legends, as well as the original English-language Dreamcast version, have stronger censorship of mature content.
[19]  All traces of cigarettes are removed, shops serve Loqua juice instead  of alcohol, and one female character's attire is altered to be less  revealing.
[19]
 [edit] New content
 24 new discoveries are in 
Legends. These are scattered  throughout the game and reduce the difficulty somewhat as they act as a  very large source of income for the player. In addition a potential 
lookout,  Domingo, can be recruited earlier. Another alteration between the two  versions is the inclusion of Moonfish and a ship flying near Sailor's  Island flown by a doctor, Doc, and a young girl named Maria. Maria has a  pet bird, which turns out to be a Hamachou. Moonfish, fish which are  invisible to the naked eye, are placed throughout the game for the  player to collect. When prompted by the distinctive sound Moonfish make,  Vyse is able to see Moonfish with a special adjustment to his headgear.  When returning these Moonfish to the Doc, Maria's bird begins to grow,  and eventually it turns into a fully grown Moon Hamachou and is added to  the journal as a Discovery.
 Another addition to 
Legends is Piastol, a woman who hunts air  pirates under the nom de guerre "Angel of Death". Piastol is after Vyse  because she mistakenly believes that he killed her father, Admiral  Mendoza of Valua, seven years before the story began. One night, her  father's ship, the 
Aquila, caught fire. Dyne's Blue Rogues saw  the ship aflame and staged a rescue mission to find survivors. However,  Piastol thought it was they who set the ship alight and attacked the  first person she saw, which was Aika. Aika came unarmed thinking it was a  rescue mission, so Vyse defended her from Piastol's throwing knife and  received a scar on his cheek which remains to this day. When Mendoza's  corpse was found and examined, it turns out it was a sword wound that  killed him instead of the fire. From then on Piastol planned to avenge  her father's death by hunting down any and all air pirates. It is later  revealed that Piastol is Maria's older sister, who was traumatized by  the same incident and believed her sister to be dead. Piastol is armed  with a scythe and Eterni spells, along with a Deathhound at her side.  She has an attack called Tempest Dance, which becomes longer and more  deadly each time Vyse and company fight her.
 A third major addition to the 
Legends version is the inclusion  of a wanted list, with large bounties to be rewarded when the player  defeats any of these foes. While some of the 
NPC's  on the wanted list are present in the original, most of them are  entirely new to the GameCube version. As with the new discoveries, the  "Wanted List" provides another source of income for the player. The  "wanted list boss battles" are markedly more difficult than the rest of  the game (including the other boss battles), partly because they level  up when the player characters do, meaning that they will be consistently  difficult regardless of the player's current level.
 Also added were the three secrets which could be unlocked by getting  most of the requirements for Vyse the Legend. A new discovery, a new  music track for Nasultan and post-attack Nasr, the best set of swords  for Vyse, and a murderously hard battle against an old "friend."
http://en.wikipedia.org/wiki/Skies_of_Arcadia#Skies_of_Arcadia_Legends