F-Zero GX Cheat Codes Unlock Gold Parts After 23 Years

While being on the F-Zero Shop screen; the arrows are D-pad-button presses:

    One-controller inputs:
    All AX Machines Unlocked
    X Y < > Z Z > < Y X Z Z Y Y > > >

    Dark Schneider Unlocked
    Z Z Z X X X X Y Y < < > > > Y Y

    All AX Courses Unlocked
    X X < > Y Z Z Y < > X < > Z X > < Y Y

    Four-controller simultaneous inputs (gold parts):
    Thunderstorm
    X Z Y Z X Z Y X

    El Dorado
    X > X Z Y < < Z

    Chrono Symphony
    < > Z > < X > Z

    Bahamut
    Y Y Z > < Z X Y

    Glacator
    > Z X < < > Z X