Games usually have premultiplied lights, such as Half-Life and that. Their dynamic lighting really consists of premultiplied lightmaps being superimposed at certain degrees of translucency. Where you'll see the "dynamic lighting" is on the gun you're holding in your hands, which may have a green glow under it with a yellow one above.

And remember the (stupid) principles of lights on computers: anything that is 0 will be black no matter what. It's really a LDR problem, though, which is a whole 'nother ballgame.