Rebel Assault

After the LucasArts logo, move the joystick in this order: up, fire, down, fire, left, fire, right, fire. If you did it correctly you'll be rewarded with a phone ringing and two people saying "Lucasarts". Then use these key combos to do things-

To go to chapters 1-9, hits the keys 1-9.
To go to chapters 10-15 hit A-F
Hitting the + key on the numeric board resets your damage to none
Press the ESC key to move on to the next cutscene