More Cars: At the Galaga Now Loading screen, destroy every enemy ship and get a perfect score. When you start the game, more cars will be available to choose from.
Race backward on normal tracks: Start a race on any of the tracks and turn the car around right before you get on the main track. As you speed toward the starting line, you see a wall and a sign that tells you are going the wrong way. Drive through the wall and now you can race backward against the computer-controlled cars.
Race backward on extra tracks: Start a race on any of the extra tracks. From the starting line, turn the car around when you reach 60 mph. A wall appears at the starting line. Drive through the wall and race the track backward.
Rotate the Flag: At the title screen, simultaneously hold L1 and R1 and press Start. The flag turns transparent. While holding the top buttons, you can use the control pad to rotate the flag.