How to unlock mini-games:
Dodge Balls mini-game: Get the eight treasures in Greenhorn Ruins
Gold Digger mini-game: Get the eight treasures in Shivering Mountains
Heads Up mini-game: Get the eight treasures in Horror Manor
Jumpin' Rope mini-game: Get the eight treasures in Beanstalk Way
Lickety-Split mini-game: Get the eight treasures in Mirror Mansion
Munch-A-Bunch mini-game: Get the eight treasures in Pecan Sands
UFO Assist mini-game: Get the eight treasures in Wonky Circus
Wario Whirled mini-game: Get the eight treasures in Greenhorn Forest