NOTE: To get the following racers, you must race all original 8 racers on one course. Race them all on the Half Pipe course for quicker access.

Press either one of the top L or R shift buttons for the next character select screen and keep holding either L or R for the following characters, and press A or C to select you character.

Dog: Hold L on Baldy
Girl Boy: Hold L on Boy
Alien SpaceCraft: Hold L on Alien
Mini SpaceJet: Hold L on Racer
Penguin: Hold R on Baldy
Anime Girl: Hold R on Boy
Alien SpaceCraft: Hold R on Alien.
Pixel Man: Hold R on Racer

Change the Time of Day:
With the "Time Progress" option turned off you can choose the time of day that you wish play. To enter these codes you must enter them after you choose your character. Hold the code until the game begins.

Sunrise - press and hold Z, Left, and A
Sunset - press and hold Z, Right, and A
Night - press and hold Z, Down, and A

Hidden Courses:
NOTE: You must race ALL original 8 racers on one course before you can use this code. When selecting the following race courses press and hold L + R until you have selected the course.

Extreme 00 = Asteroids
Extreme 01 = Artificial Valley
Extreme 02 = South Pole
Extreme 03 = Astro Pipe

Thanks to Revolution reader Joe Forest!