At the Mode Select screen, press L, Z, R, C-Up, C-Down, C-Left, C-Right, Start. You should hear a chime if you did it correcly.
To change your car's colors, press the R-Button during the car customization screen. Note that there are only a few select colors for each vehicle.
Beat the Jack, Queen, King and Joker Cup on Novice, Standard and Expert difficulty to see the game's end credits. After resetting the system, the title screen and intro music will change and the final row of six cars will be selectable.
If you beat a certain time in the Time Attact Mode, you will unlock a ghost which is hard to beat (harder than the Master Mode.) Here are the times:
Mute City 1:23:000 Silence 1:13:000 Sand Ocean 1:15:550 Devil's Forest 1:23:000 Big Blue 1:35:000 Port Town 1:36:000 Sector A 1:22:000 Red Canyon 1:19:000 Devil's Forest 2 1:24:200 Mute City 2 1:19:000 Big Blue 2 1:07:000 White Land 1:40:000 Fire Field 1:23:000 Silence 2 1:35:000 Sector B 1:45:000 Red Canyon 2 1:40:000 White Land 2 1:13:000 Mute City 3 1:46:000 Rainbow Road 2:11:000 Devil's Forest 3 1:20:000 Space Plant 2:04:000 Sand Ocean 1:35:000 Port Town 2 1:52:700 Big Hand 2:27:000
To get the Joker Cup and six additional tracks, beat the Jack, Queen, and King Cup on Standard difficulty.
If you beat the Jack, Queen, King, and Joker cup you'll get extremely hard Master Difficulty.
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.
While driving tap R and Z repeatedly. After that you will spin, glowing red and yellow.
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.
At the customization screen press the C-Buttons to rotate the car in all directions.
Towards the end of Sector B on the hill right before the end use a boost or two and when the wall disappears turn to the left and fly straight onto the finish line.
At the car select screen press and hold the (L) and (R) buttons. While holding those buttons press C-LEFT and C-DOWN to shrink the cars.
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.
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.