The Code Book and the Dark Game have the same main idea, even though they put the main idea in different ways. The code book describes the main point with events that actually happened. The Dark Game uses a hypothetical situation to describe the main point. These two stories have many differences and similarities.
The Dark Game has a hypothetical story which The Code Book doesn't. The author uses narrative style, which is how he tells the story. He uses vivid description like you would do for a regular fictional story. The Dark Game also has thoughts of a spy. This is important e=because the readers can see how the spies do their work and what they are thinking. It is also conversational.
The Code Book has real life events that actually happened.