Difficult. As you want to do something realistic (stargate) the first screen was indeed too cartoony even if it was looking better. Well, I am only comapring the two last screenshots in this thread.

Halogeenröhren usually have slightly blue light, like in the first shot. In the second shot is yellow light like from glühbirnen or sunlight.

The second shot is more realistic, what I think is what you want. To make it perfect you would need to make a better transition between the different textures. But that would mean that you would have to draw alot of single textures, what is more work as you can do as a single man team. So stay happy with your imperfect result and go on to learn more about making games.