During the boat qualifying race, always cross the finish line in reverse using 2. If successful, you will hear a sound confirmation. Now all vehicles are very fast.
Always Place 1st
On The Breakfast Bends, turn around and complete the course backwards. If successful, you will hear a sound confirmation.
Exploding opponents
On The Breakfast Bends, head to the very top left corner of the course, then press 1 + 2. If successful, you will hear a sound confirmation, and any vehicles that touch you will explode.
Hard Mode
On The Breakfast Bends, head right across the track until you see the face splodge. Go inside the splodge and press 1 + 2. If successful, you will hear a sound confirmation.
Level Select
Press Up, 2, Down, 2, 2, Left, 2, 2, 2 at the title screen.
Super Grip
While on a breakfast table, stop on a puddle of milk and press Up+1+2.
Unlimited Lives
By falling off the first breakfast table on the bottom right hand corner you will gain infinite lives.