What was the first gun game?

The first arcade type of game with a gun appeared in the 1920s. It was called the "Automatic Pistol Game" and was purely a mechanical game. Later, in the 1940s, "Ray Gun" appeared; it was tethered to a big monitor and had many electronic elements to it.

In the 1960s, Ralph Baer invented the Brown Box which used a rifle that was made for a video game. The Brown Box later became the Magnavox Odyssey, which is considered the original console gaming system. It wasn't until 1975 when the first video game that actually showed a gun in the game appeared. This was an arcade game called "Gun Fight."