When you have more time to talk about games, than actually play them.
First Person Shooters (FPS) gained popularity ever since the days of Doom and Wolfenstein. For the longest time, games were played from the top down perspective, or as side scrollers, but the first person perspective provided more immersion for the player. They could more easily imagine they are in the game.
Most games of the FPS genre were gallery type shooters where you move from room to room with a minor story element. Once Half Life came onto the scene, it revolutionized the genre with scripted story elements and puzzles. It wasn’t all about shooting, there was some thinking and narrative involved. Half Life 2 took it even farther with better graphics and physics based puzzles.
These days, the Call of Duty franchise reigns supreme in the land of FPS. When COD showed up, it included scripted story elements in a war story. There weren’t any crazy puzzles like HL, so a different set of players loved the action packed gunplay and story. They really took off with their multiplayer action in later iterations. It has even become an E sport. It is fast paced and all the difference is made in fractions of a second.
FPS gaming innovations have been made since the humble beginnings, but the basics stay the same. Stories have often become more complex, but it will still require aiming down the sights as if the gun was held up to your own eye. Animations, effects and sound effects improve, but that core gameplay will likely always be there. Only VR offers the real game changer where you are really IN the game, physically aiming the gun.