On the high score screen, type "SKID ROW". Not sure if this does anything other than put {18 and life} as your name on the high score table.
At any time, type "QUIDITY" and use the following keys:
'SPACE'-----------Skip levels
'HELP'--Toggle infinite lives
'F4'----------NTSC video mode
'F5'-----------PAL video mode
NOTE: If the game ends or you reset the game by pressing 'F1' you will have to enter the code again.