George Martin opens his "Filthy Pro" section with the story "The Hero". For the first time in this collection we are introduced to Martin's visions of alien landscapes and science fiction ideas.
What I find especially interesting here is that the story of bleak betrayal of a soldier trying to retire and return home to Earth is that the underlying darkness of "The Hero" is apparent in the earlier stories in the collection and very likely (almost positive) that the subsequent stories will have that touch of darkness.
So far in the collection Martin's stories are reasonably simple and straightforward with a bit of a twist at the end. Martin is best known for his A Song of Ice and Fire fantasy series which is noted for its complexity and I imagine that when we get to his award winners we will see deeper complexity.