I dunno if I'm the only one who feels the same way about this
But there is no reason for Atlantica to exist in KH 2 for simply two facts:
1The world itself is barely canon,there is neither heartless nor nobodies roaming this world at all,nothing related to Organization XIII is revealed and Ursula is no longer involved with neither the heartless nor Maleficent
2During my playthroughs,I found out that you can finish the entire game without touching Atlantica or a single song in it once....I'm not kidding
During 3 of my playthroughs of KH2 I completely skipped Atlantica and didn't finish a single song in it...which begs the question:If this world isn't invaded by the Heartless nor the nobodies....why do Sora,Donald and Goofy need to visit this world again???
Well,it turns out that there are certain items and spell upgrades that you can only get here with the addition of the keychain that you get after finishing it
It's pretty much became another 100 Acre Wood.You don't have to do it,but it's there for you to get some items and spells that will ease your journey
Aside from that,you do nothing related to the story in Atlantica
I dunno if I'm the only one who feels the same way about this
But there is no reason for Atlantica to exist in KH 2 for simply two facts:
1The world itself is barely canon,there is neither heartless nor nobodies roaming this world at all,nothing related to Organization XIII is revealed and Ursula is no longer involved with neither the heartless nor Maleficent
2During my playthroughs,I found out that you can finish the entire game without touching Atlantica or a single song in it once....I'm not kidding
During 3 of my playthroughs of KH2 I completely skipped Atlantica and didn't finish a single song in it...which begs the question:If this world isn't invaded by the Heartless nor the nobodies....why do Sora,Donald and Goofy need to visit this world again???
Well,it turns out that there are certain items and spell upgrades that you can only get here with the addition of the keychain that you get after finishing it
It's pretty much became another 100 Acre Wood.You don't have to do it,but it's there for you to get some items and spells that will ease your journey
Aside from that,you do nothing related to the story in Atlantica