During play, type "KAREN" for invincibility. A flashing cheat icon will appear in the upper left corner to let you know it worked. Now use the following keys:
'F1'-------Jump to part one of the current level
'F2'-------Jump to part two of the current level
'F3'-----Jump to part three of the current level
'1'-'5'----------Jump to the corresponding level
'U'-------------Flip screen upside down and back
'R'------Restart current level and collect bonus
'W'--------------------------------Select weapon
'D'--------------------------Program information
'G'---------------------------------Add grenades
'M'--------------------------------Add gun clips
'.'----------------------------Add to life meter
'ENTER' (keypad)--Kill all enemies on the screen