Hardcode mode (advanced physics):
Press Up, Down, Left, Right, R1, Up, Down at the main menu.


Disable strict mode in beat-the-heat mode:
Press Up, Down, Left, Right, R1, Left, Right at the main menu.


Hornball mode:
Go to the race day screen in single race mode, press Up, Down, Left, Right, R1, Up, Up. Start a race and shoot a ball (press Up). Then go to practice mode and press Up, Down, Left, Right, R1, Down, Down.