Hold Z + L + R and press C-down (x4), C-right, C-up, C-left at the main menu. (A flashing green screen confirms correct entry.)

Hold Z + L + R and press C-up, C-right, C-left, C-down, C-up, C-right, C-left, C-down.

Hold Z + L + R and press C-up, C-down, C-left, C-right, C-up, C-down, C-left, C-right during game.

Successfully complete Race Competition mode with at least a Bronze medal to unlock the Velocitar course.

Alternately, hold Z + L + R and press C-left, C-right, C-up, C-right, C-left at the main menu.

Hold Z + L + R and press C-left, C-right, C-down, C-left, C-right, C-down, C-up at the main menu to inflict twice the damage.

Successfully complete all three Challenge modes.

Successfully complete Time Challenge mode, finishing third or better.

Hold Z + L + R and press C-down (x2), C-left (x2), C-right (x2), C-up during game.

Place first in all races of a particular type to unlock the Gold Challenge for that series of races.