Tumblr - NANI?!

when you pull the trigger the screen quickly turns black except where the ducks are, they turn into white squares. if the light-gun sees the white boxes it counts it as a hit.

Fun science fact: light is absorbed by black surfaces and reflected by white surfaces so the scanner only "sees" the white surfaces.
Also if you're swiping a card with magnetic strip and it doesn't read, swipe it again faster instead of slower.