I think the whole explanation for the bullet time in the game was that said faceless protagonist was "off the charts" concerning his reflexes, said sometime in the intro scene of the original game.
I never finished the original game. I kind of got bored of the same environments over and over. "Oh, boy, another abandoned office building! More apartments! Let's go through 5 dozen levels of parking garage, and yes, there will be 2 clones behind the left-side cover and 1 behind the crate to the right, and one waiting to jump you just around the corner." Plus there was never really a reason to use your melee except the once where the tutorial said or if you were out of ammo (which never happened), so one of the more exciting points of combat got completely left out.