Get the Special Glasses.
Defeat Super Pumpkin Bros
Kill 20 ghosts.
Get the Binoculars.
Defeat Big Marshmallow Boo
Kill 10 ghosts.
Get a Stamina extension.
Kill your first ghost.
Get the Helmet.
Get a heart extension.
Recover a heart
Get your first silver key.
Get your first golden key.
Solve your first puzzle.
Get the Gloves.
Get your first bonne.