Enter the following at the Main Menu:

All bikes and tracks    C-Up, C-Left, C-Left, C-Right, L, R, C-Down, Z 
Scooter Mode C-Down, C-Right, C-Up, C-Left, Z, Z, L, C-Left 
Be the Cop Mode         Z, C-Left, C-Down, C-Left, Z, L, R, C-Down 
Faster BikesC-Up, C-Left, C-Left, C-Right, L, R, C-Down, Z 
Girl bikerC-Right, C-Left, Z, L, R, C-Up 
Level 2R, C-Right, Z, R, L, C-Up, C-Left, C-Up 
Level 3R, C-Right, C-Right, C-Right, R, C-Left, C-Down, Z 
Level 4R, C-Right, C-Down, C-Left, C-Right, C-Right, Z, L 
Level 5Z, C-Right, C-Down, C-Left, C-Right, C-Right, Z, L
Infinite 4X     L,L,R,R,L,C-UP,C-RIGHT,Z
Infinite Damage *2 Left, Left, Left, Left, Right, Right, Right, Right
All Weapons     C-Up, C-Up, C-Up, C-Up,C-Down, Left, C-Left, Z
Insanity Level  C-Up, C-Left, C-Left, C-Right, Left, Right, C-Down, Z

Thanks to Revolution readers Raymond Hutchinson, Trey Guyton, Darren Young,

Kyle Witter, Nate S., Shawn Nixon, Forsberg, Martin O’Donnell Jr., Bill Harrell,

Matt Lasky, Eric Lingerfelt, Brian Vischer and Brandon Prince!