Programmer credit:
Select game 13 and allow the incoming missiles to reach your cities, and fire all your missiles without scoring any points. The city on the right side will turn into "RF", the initials of programmer Rob Fulop.

Extra points:
Aim and fire three missiles at the highest part of the screen when game play first begins. Press Reset before the missiles explode. The missiles will remain in view and a varying number points will be added to your score after they explode.

Missiles on game selection screen:
Start a new game and start pressing Select while some missiles are shooting down. The missiles will keep flying as you cycle through the game variations.