For linear content, movies are a great model.
- There are back stories, giving necessary context and information, which some directors play out seamlessly and some do not.
- Another technique is to have a character be the audience proxy and to ask the questions or make the statement that most people in the audience would ask. "Why don't you just go to the police?" or "You had an affair? What are you, crazy?"
In Half Life 2, there are creatures that are mounted to ceilings with long tongues hanging down that grab things and pull them up to eat them.
One technique to inform the player might have been an encyclopedia-like screen giving some information about these creatures. Another would be to have a virtual colleague say something like, "Careful - those tongue creatures are hungry and once they grab you, it's over."
Instead, Half-Life 2 carefully builds the awareness in the player, and then pushes it. They first (in this screen shot) show the player what these creatures do by, in this case, having an unwary crow get scooped up. Then they expose the player to simple situation with a single creature. A few levels later, the player has to get through dozens of these creatures using increasingly clever techniques, including improvised hybrid strategies learned from other parts of the game.
The Instructional Design fascists say, "tell them what you are going to tell them, tell them, tell them what you told them."
What they are really training their audiences is how to be idiots.
Thank goodness computer games have more respect for our intelligence.