Walkthrough
After completing Echo's Edge, you will progress to Nature's Navel on Planet Popstar. This level is quite volcanic in nature, having numerous magma pits and a variety of spinning blade hazards found throughout. There are no Mini Bosses or Bosses found in this level, just a Hidden Switch to unlock another extra stage and the usually Rainbow Puzzle Piece.
Once in the third area of Nature's Naval, directly below where a Chilly Enemy is found, you will find a ladder that will lead you straight underground to a flaming chain. After disposing of the chain, head into the door below it. Before you know it, you will find the Hidden Switch. Activate it to unlock the Duplex Dream Stage.
Before going through the final door of the level, head left and hover up. You should quickly find a ladder, one that should lead you straight to the Rainbow Puzzle Piece found in this level. After obtaining it, head for the final door to proceed in your journey.
Copy Abilities
Cleaning, Cutter, Fighter, Ice, Ninja, Stone, Water, Wing
Bio Spark, Birdon, Broom Hatter, Chilly, Dekabu, Driblee, Kabu, Knuckle Joe, Propeller, Rocky, Shield Enemy, Sir Kibble