Galaga

Galaga had another key ingredient of a respectable arcade atmosphere; a warm melody for the background music and various other familiar sounds that made u reflexively check ur pocket for quarters.. this game also had an excellent upgrade feature; submit ur ship to a particular enemy and safely shoot that enemy down, and you can double ur firepower.. truly the first arcade implementation of a 'sacrifice'. i would always mistaken this game for 'galaxian' which did not have the double-power/sacrifice feature, and for that, was always a disappointment.