To enter extreme mode on 1 Player VS mode, highlight the hard setting and hold L and up and press start. The background should change to red.
Remove stop command:
To remove the stop time when you clear a combo/chain, at the start when Yoshi says "Nintendo" press B,A,L,L. A sound will confirm the code.
Play Rescued Characters:
In 1 player VS mode push X and Y buttons untill you strat the match. You will be directed to the player select screen.
Play as Rival Characters:
In 2 player VS/Time Trial mode push L and R on BOTH controllers. The rivals characters will appear.
To access the hidden puzzle stages in puzzle mode, enter this code in the Password Game "FP5D29J!"
How to control the cursor in "How to Improve Mode":
In any of the sessions hold down the "R" button. You can now control the cursor and try out the chains, combos, and skill chains on your own.
In the ending credits for the VS mode hold select and use the D-Pad to control Yoshi.