To enable Debug, while on the game menu screen, press the following button combination C-RIGHT, C-RIGHT, C-LEFT, C-LEFT, L, Z, C-LEFT, C-UP. A sound will confirm if the code has been entered correctly and blue debug bars will appear on the screen.
Just like the debug menu, the following codes can be entered to select a level.
Level 2: R, C-RIGHT, Z, R, L, C-UP, C-LEFT, C-UP
Level 3: R, C-RIGHT, C-RIGHT, C-RIGHT, R, C-LEFT, C-DOWN, Z
Level 4: R, C-RIGHT, C-DOWN, C-LEFT, C-RIGHT, C-RIGHT, Z, L
Level 5: Z, C-RIGHT, C-DOWN, C-LEFT, C-RIGHT, C-RIGHT, Z, L
For all bikes and tracks
C-UP, C-LEFT, C-LEFT, C-RIGHT, L, R, C-DOWN, Z
"Scooter Mode" (unknown what it does really, I see no scooters)
C-DOWN, C-RIGHT, C-UP, C-LEFT, Z, Z, L, C-LEFT
Be the Cop Mode
Z, C-LEFT, C-DOWN, C-LEFT, Z, L, R, C-DOWN
C-RIGHT, C-LEFT, Z, L, R, C-UP
Enter Gameshark code "810A77D6 0001" to unlock all tracks.
Enter Gameshark code "810A77C8 0001" for debug mode.
Enter Gameshark code "810A77D4 0001" for Scooter mode.