Hold L + R and turn on the Game Boy Advance. Select "Yes" at the prompt to delete your game saves.
Dirty Joker
Win the Pawn, Knight and Bishop tracks under the standard difficulty setting.
Stingray
Win the Pawn, Knight and Bishop tracks under the expert difficulty setting.
Master difficulty setting
Win the Pawn, Knight, or Bishop series under expert difficulty level in grand prix mode to unlock the master difficulty for that series.
Silver Thunder
Win the Queen tracks while playing the expert difficulty setting.
Jet Vermilion
You can unlock Jet Vermilion by unlocking all other cars and completing championship mode 255 times. Or beat every series on Master Class with all other racers.
Fighting Comet
Win the Pawn, Knight, Bishop and Queen tracks while playing the master difficulty setting.
Falcon Mk.II
Win any set of tracks while playing the expert difficulty setting.
Soft reset
Hold down the A, B, Start and Select buttons.
Demo Mode
At the title screen, press select.
Password Screen
At the machine selection screen in grand prix mode, press L, R, Start, R, L, Select.
Open All Tracks
Press B, Left Trigger, B, A, Right Trigger, B, B, A, A.
Slower Opponents
A, Right Trigger, L, B, A, A, B, Left Trigger.
Faster Cars
Press A, B, Left Trigger, A, A, Right Trigger, B.
Get Queen mode
To get queen mode, beat all the expert settings on pawn, knight, and bishop. Now, when you go to the course select, it'll be there.
Unlock Championship Mode
Not to be confused with the standard Grand Prix Mode, Championship is a hidden option that lets you race a Time Attack challenge against a ghost car on a specialy Synobazz track. The mode also offers the ability to see a replay of the winning run, complete with button commands display. To unlock it, register your name in the rankings of every race in every series.
Hint: Turn sharply
Press A repeatedly while turning to turn without hitting the forcefield.