During play press the 'SPACEBAR' to view the options screen.  Move
down to the VIEW GAME SCREEN option and push the JOYSTICK LEFT and
hit FIRE.  The game screen should appear.  Center the joystick and
press fire again.  The option screen should now reappear.  Move down
to the SOUND ON/OFF option and push the JOYSTICK RIGHT and hit FIRE.
Now go back up to the VIEW GAME SCREEN optionand push the JOYSTICK
RIGHT, while holding the joystick in this direction hold down the
RIGHT MOUSE BUTTON and press the LEFT MOUSE BUTTON.  The option
screen should change to cheat mode.  Now go to resume game and press
the fire button.  You now have unlimitted shields and can select any
level on the options menu.  If it doesn't work repeat the whole
thing over (start by resuming the game and pressing the 'SPACEBAR'
to go back to the options screen.

NOTE: This next cheat only works with the full price game not
budget release.  On the option screen, type "AL YANKOVIC" then
press 'F5' for an effect.  Also pressing 'X', 'C', 'T' and 'SPACE'
keys produces a cheat screen.