Secret Track
Choose "Wreckin' Racing", then "Championship" and enter the name
"REFLECT!". Now go to the main menu again and choose "Wreckin' Racing"
again. This time, choose "Practice". At the track selection screen,
you should see the new track.
Invincibility
Follow the steps above, but enter "!DAMAGE!" as your name instead.
Select Number of Racers
Follow the steps for 'Secret Track', but enter the name
"NPLAYERS" instead.