Well, im not sure in anyway how it worked, but i think that when you make a hud (the damage hud for example* what is black is transparent i belive. He would have done something to do with transparency probably, im not sure, And the ambience being set to 0, with diferent lights affecting them, is because, they are emiting the light, which the ambience does not affect (im pretty sure, its been a while since a worked with darkness)
I think he would of had to used a hud, or some form of it anyway, and then scripted the rest.
Im guessing it would be possible, to have a white dot, in the middle of a black square, and have an FPI script, and create a flashlight off of that.
Thats a guess based on what i know from GameMaker back in the day
~ Benny Boy 2321 ~ Raw Sandvich ~