All Characters, Boards and Levels:
     At the Title screen press Z, B, C-Up, Down (D-pad), Left (Stick),
Right (Stick), Up (D-Pad), R, Z, A

Expert Mode:
     Complete Story Mode to access Expert mode.

Bonus Characters:
Mr. Penguin Defeat him in Training Mode.  
Damien Complete the entire Story Mode.  
Mr. Dog Complete the Shoot Cross test.  
Panda In battle mode, select Mr. Dog wearing his space suit. 


Unlocking the Ice Snowboard:
     Beat  the  Snowman  Boss  track  on  Expert  Mode.  This board is
slippery and hard to control.