Water WorldThis boss is a giant fish. Cookie should drive the boat and Cream should follow in the inter tube. Get Cookie to steer Cream to get bombs so that when the fish is nearby and above the water Cream can throw the bombs at the fish boss. Make sure you get the times. Music WorldYou must beat the boss by continuously hitting the keys where his arms are until the arm moves. Then press the new key. Keep doing that as he loses arms.
Desert WorldThe boss is a giant totem pole. Cookie needs to try to hit the layers off the totem pole with a hammer.
Jungle WorldCream lures the boss over and cookie should jump the on buttons and the logs hit the boss.