Hidden message from Yoshi
At the end of each and every Mini-Game, get enough for a heart fruit and then eat it. After all the letters appear, put them in the right positions, and you'll get a hidden message from Yoshi.
Instant death
During gameplay, press the L Button, Z Button, A and B simultaneously.
Yoshi colors
White and Black Yoshis appear as Giant Eggs, but will hatch after completing the level.
Black Yoshi
Hidden in Levels 2-1, 2-3, and 2-4.
White Yoshi
Hidden in Levels 3-2 and 3-3
Yoshi's color in Practice Mode
In the Trial Mode, pick the color of Yoshi that you want and press Start and Z at the same time. Then press B to go back and go to the Practice Mode, and you will have the color Yoshi you chose.
Hidden message from Yoshi...