Unlock Selected 1: Dodge Balls
At Greenhorn Ruins get all 8 treasures.

Unlock Selected 2: UFO Assist
At Wonky Circus get all 8 treasures.

Unlock Selected 3: Jumpin Rope
At Beanstalk Way get all 8 treasures.

Unlock Selected 4: Munch A Bunch
At Pecan Sands get all 8 treasures.

Unlock Trial Version 1: Wario Whirled
At Greenhorn Forrest get all 8 treasures.

Unlock Trial Version 2: Heads Up
At Horror Manor get all 8 treasures.

Unlock Trial Version 3: Gold Digger
At Shivering Mountains get all 8 treasures.

Unlock Trial Version 4: Lickety Split
At Mirror Mansion get all 8 treasures.

Earn the Best Castle
Find all 40 Spritelings before beating the final boss to get the best castle (and best ending).

Infinite Coins
When fighting DinoMighty, grab her tail and wait until she raises it above her head. Perfom a Ground Pound (A + R Button). She'll drop a lot of coins. This stuns, but does not damage her. Repeat as often as you like to get an inifinite number of coins.