Gore Mode
This will cause you to bleed instead of smoke.
Press Z, Down, C-u, C-l, C-l, C-l, C-l, C-d.

Bypass The Ads
When you turn the game on immediately reset it and you’ll be able to press start to skip over two minutes of ads.

Turbo Crazy Mode
Press B, B, R, Up, Left, Down, C-u, C-l to get Infinite Nitro.

Psychedelic Mode
Press A, R, Left, Right, Down, C-u, C-l, C-d to make the levels constantly change colors.

Wire Frame Mode
Go to the "Push Start" screen and complete the following:
L, L, R, Z, Left, Right, C-u, C-r. "Wire Frame On" will flash on the screen. Just repeat the code to turn it off.