If you type "KILLER" during the game, the screen will flash, activating the in-game trainer and infinite lives. You will now be able to start on any level, by using the function keys 'F1' - 'F8'.

During the intro, press 'Esc' then type "POORTOKI". Start the game and press 'Esc' once the map screen has passed. Then pressing function keys during the intro will allow you to skip levels.