Impact Racing

Invincibility from David Robbins
enter the code "I.AM.IMORTAL"

Other Codes from Gail
ALL.TOOLEDUP - Infinite shields
BONUS.LEVELS - Play all of the bonus stages in succession
RABBITBADGER - Adds a "Skip Level" option to the "Pause" menu
ENDGAMELEVEL - Warp to the game's formal stage
JOURNEYS.END - See the end sequence and credits