Duck Hunt works by placing real, live, miniature fowl in your television set and providing you with a specially-constructed firearm that shoots invisible rounds that have the ability to pierce your television screen without physically damaging it. So when you fire the gun at the TV screen, an invisible bullet is silently expunged from the barrel, through your television screen, and into the depths of tele-reality, where it strikes the miniature digital winged animal, rendering it deceased.

- From the original booklet that came with the game