The “zapper” (the gun) is just a light detector. When you pull the trigger while playing duck hunt, it does 2 things:
* turns on the light detector
* makes the screen pitch black except for a white square wherever a duck was
If the gun is pointed at the bright square the light detector will notice and register a hit.
If you point the gun at a light source like a brightly lit bulb it will always register hits.
I’m not sure how it resolved *which* target you hit for rounds with multiple targets, though.
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