In ninja gaiden 2004 I got my ass killed until I just knew how to beat various enemies. At that point it's no longer a case of "keeping up" visually with their speed but instead a lot of muscle memory, audio cues and knowledge of how enemies behave plus what weapons/moves work best against them.

Surely no one actually keeps track of everything individually purely within the scope of the camera and react to almost exclusively to that visual stimuli?