Once the game is loaded and prompts you to press fire, press the "SPACE BAR" instead. You will be able to change the speed of the enemy bullets and other stuff, with the mouse and keyboard. On the high score table, type "COMMANDER" on the high score screen (not as your name) press 'F7' to activate the super weapons 'F1-F6'. You should also be invincible. 'F10' turns cheat on/off and 'F8' advances a level. On the title screen press 'SPACE' or 'ESC' for an options menu.