Alright, so I've covered the sound effects, but what if you could designate certain areas where the lights actually make shadows?
Imagine that you're running through the tunnels in ctf_equinox trying to run away with the red flag. Suddenly, you spot a rapidly lengthening shadow ahead of you and you shoot, killing the red defender because his shadow from the light behind him gave away his position.
Perhaps it would just be another aesthetic addition to half-notice as you move around the level but I think that it would give particularly dark levels a whole new feel.
Imagine that you're running through the tunnels in ctf_equinox trying to run away with the red flag. Suddenly, you spot a rapidly lengthening shadow ahead of you and you shoot, killing the red defender because his shadow from the light behind him gave away his position.
Perhaps it would just be another aesthetic addition to half-notice as you move around the level but I think that it would give particularly dark levels a whole new feel.