I really like this presentation of the subject on Blender Guru's youtube channel
. Starting at 11:24 he talks about complementary colour-schemes.
I also agree with him, that images work best when there's a clear dominant and recessive colour. I tend to feel - especially with red-green - that the more equally they are used, the more tension there is in the piece...with two opposing colours competing for your attention. I think your Conquest of the Long Bow suffers a bit from that, while Gabriel Knight and Beneath a Steel Sky have a much more cohesive feel. Of course that can also be due to technical (palette) limitations.
Nice job on the examples. They clearly show the effect and different usages.