On the Main Game screen (where you pick your mode), press the following: L, Z, R, C-Up, C-Down, C-Left, C-Right, then Start. If you've done it correctly, the screen will blur, then reappear as normal.
On the vehicle select screen, while holding the L and R buttons, press left C and bottom C simultaneously. All vehicles will be small until you complete the current circuit.
On the Adjust Your Machine screen, press the R button repeatedly to scroll through the various paint jobs. Do you have anything in mauve or puce?
On the Adjust Your Machine Screen, press the C buttons to view your vehicle from different angles.
X-Cup Track Generator
Beat all four cups on Expert difficulty to open F-Zero's hidden X-Cup. This cup will randomly generate six courses, ranging from utterly boring to plain cool. Beating the four cups will also open a Master Difficulty level.
Title Screen Changes
To have the title screen change to a comic book motif, beat F-Zero X on Expert. For a second change, beat the game on Master difficulty.
To use the spin attack just hold the Z botton and tap R twice or just do the reverse.(This method is very useful in "Death Match" if you time it just right).
Rainbow Road Shortcut
At the top of the first big drop, drive off the side of the track and tilt backward. Starting from 30th, this will put you anywhere from 20th to 1st, depending on how well you pull it off.
Mute City II Shortcut
Right after you make the third hard turn, you will see a ramp to the left that looks like it will lead you off track. If you hit it with a booster, you will fly over the gap and onto the next strip of tracks.
End Credits and Final Six cars
Beat the Jack, Queen, King and Joker Cup on Novice, Standard and Expert difficulty to see the game's end credits. After resetting the machine, the title screen and intro music will change and the final row of six cars will be selectable.
Fall through track in Port Town
To fall to in Port Town first you have to be on the second lap then right before the first speed boost use the booster. In the air, turn untill you see two signs. Then, land.