Bubble Bobble

To give you an easier time playing the game, simply enter the following control sequence on the title screen before it disappears:
Left, Jump, Left, 1P Start, Left, Fire, Left, 1P Start.
If done correctly, the words, "POWER UP!" will appear at the bottom of the screen, and you'll have super speed and rapid fire when you start the game. This cheat also works on Bobble Bobble.