The NES Zapper was an accessory that most people used for Duck Hunt. However, there were a bunch of other games that utilized the light gun as well. Some games required it, while others allowed the player to use it optionally. The games to the left are all Zapper-compatible.
Since it came with the most NES console bundles, nearly everyone had one of these. Some refer to this as the “light gun” because it worked by detecting light. When the trigger was pulled, the screen would turn black and the target would turn into a white box. If the gun was pointed at that box, it would detect the light and shoot the target. Unfortunately, due to display lag caused by processing on modern LCD TV’s, the gun does not sync up with the screen, making the games unplayable.
The original zapper was grey before it was later rereleased in orange.