Unlock Mario

• 1). Acquire eight silver stars.
  
  
• 2). Find and enter the princess's rec room inside Mushroom Castle.
  
  
• 3). Enter the door with the number 8 and jump inside the painting of Mario that hangs on the wall.
  
  
• 4). Defeat the Goomboss to receive the key to Mario's door.
  
  
• 5). Return to the rec room and use the key to unlock Mario's door. You will enter as Yoshi and exit as Mario.
  
  

Unlock Luigi

• 1). Acquire fourteen silver stars.
  
  
• 2). Playing as Mario, enter the haunted mansion and go to the second floor.
  
  
• 3). Enter the room on the right and find the red box.
  
  
• 4). Jump onto the hidden ledge above the red box.
  
  
• 5). Obtain flower power to float up to the painting of Luigi and enter the painting.
  
  
• 6). Fight and defeat Big Boo to receive Luigi's key.
  
  
• 7). Return to the rec room and unlock Luigi's door. Enter the room, and then exit as Luigi.