I want to talk about what peoples favorite worlds are. But not just overall favorites. I want to see what everyones favorite worlds are in terms of Soundtrack, Story, and Environment as well as overall.
So you favorite world for Soundtrack would be the world with your favorite music in the game. Mine is Celestia
Your favorite world for story would the world that has your favorite plot and characters: Mine is Grizzlehiem/Wintertusk.
And your favorite world for Environment is the one you think looks best. Mine is a tie between Marleybone and Azteca.
Your favorite overall is the world that you like the best. Mine is a tie between Azteca and Grizzlehiem.
