Secret Levels Chapter 4
Go to the level which has the basketball boss and enter the room before the boss. Go to where that bad guy is standing and ground pound the floor. The shaking will lift him up. Grab him and throw it at the wall that is to the right of the boss door. When you reach the star door, you will be taken to a ghost mansion!

Secret Levels #2 Chapter 4
Go to the factory level and cross the room to get to the door. Enter it and fall down the first shaft you see. Break open the boxes for coins. Then stomp on the purple block that is second from the right. Crawl to the left and stomp the block and pipe in the middle of the area. Keep on raming into the pipes (going left) until you come to a door. Enter it and become "flat." Climb up the platforms and float to the star door.

Battle Bosses
Complete the game with 100% status and all treasure and map pieces. (Skulls denote Boss levels.) Select a Boss level then hold Down + A at the level name screen.

In-game reset
Press Select + Start + A + B during game.

Hidden chapter
Begin a new game and without waking Mario, let the pirates knock him out of the castle. The game will begin at the hidden chapter