"When the trigger on the Zapper is pressed, the game causes the entire screen to become black for one frame. Then, on the next frame, all valid targets that are on screen are drawn all white as the rest of the screen remains black. The Zapper detects this change in light level and determines if any of the targets are in its hit zone. If a target is hit, the game determines which one was hit based on the time of the flash, as each target flashes for one video frame, one after another.[24][25][26]

This darkness/brightness sequence prevents the possible issue caused by pointing the Zapper right next to or into a light bulb.[26][27][28] Older light guns did not use this method, making it possible to cheat and get a perfect hit score in a way not possible using the NES Zapper.[citation needed]

The NES Zapper can only be used on CRT displays; it will not work on LCDs, plasma displays or other flat panel displays due to display lag."