Walkthrough
By activating the Hidden Switch in Nature's Navel on Planet Popstar, you will unlock the extra level of Duplex Dream. Much like Nature's Navel, Duplex Dream features loads of the same volcanic obstacles. However, it also has some icy region similar to those found in Echo's Edge. Because of this, it's only fitting that the level be called Duplex Dream, as it has two different landscapes to it. Be prepared to face two Mini Bosses in this level.
In the third area of the level, you will find a block of Ice hiding a puzzle piece in plain view. First, melt the piece of ice behind it to find a Hidden Door. Once inside, use a Sizzle Whip to burn the next block of ice, using your whip to grab the key to unlock the next door. After this roundtrip, you will eventually find the Rainbow Puzzle Piece for the level.
Directly before finishing Duplex Dream, you will have to face two more Mini Bosses, this time both Chef Kawasaki and Vividria. By now, you should be use to most of these Mini Mosses and know exactly what it takes to defeat. However, should you want a seriously easy victory with these two, make sure to grab the Festival Copy Ability hidden the Ice to the left directly before the battlefield.
Copy Abilities
Artist, Beam, Cleaning, Cook, Festival, Fire, Ninja, Whip
Anger Masker, Bio Spark, Bronto Burt, Broom Hatter, Burning Leo, Festival enemy, Gordo, Propeller, Waddle Dee, Waddle Doo, Wester
Chef Kawasaki, Vividria