All-star team
Complete the World League at level 4 or higher. Then, press Up, C-Up, Up, C-Up, Down, C-Down, Down, C-Down, Left, C-Left, Right, C-Right, Left, C-Left, Right, C-Right, B, A, Z + Start when playing against the World Stars.

Big head mode
Press C-Down(2), C-Up(2), C-Right, C-Left, C-Right, C-Left, B, A, Z + Start at the title screen. A sound will confirm correct code entry.