Extra saved game positions:
Select the "New System Data" option, then hold L1 + R1 + L2 + R2 + Select +
Start and press Circle to increase the number of saved game positions to fifty.

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Mirror tracks:
Finish in first place on all tracks. Then, press Right at the track selection
screen.

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Alternate footstep sound effect:
Pause game play and press L1(2), R1(2), Down, Up, Circle.

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View ending sequence:
Complete all mirror tracks, then press Select at the title screen.

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Double money:
Save the game twice in different slots. Enter the bank and use the money
transfer function. Move the money from one slot to the other to double your
money.

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Bonus animals:
Purchase all five kangaroos and five dinosaurs. The blank kangaroo and white
dinosaur will now be available.

Submission: Al Amaloo (vgstrategies.miningco.com)