Each story element can be scrutinized to see if it can be made more emotionally engrossing or more emotionally complex. "Engrossing" and "complex" may seem to be unrelated terms, but more often than not, they're strongly tied.
Let's take a look at an example: In Star Wars Episode IV, Luke's final struggle to shoot a missile through a small hole to blow up the Death Star seems to be both engrossing and simple. A young man in a spaceship blows up the Death Star. Not very complex, right?
But, upon closer inspection, we can see that this event isn't simple at all. Here are some of the layers of complexity that make that scene of Luke making his final run more emotional:
We identify with Luke because of various Rooting Interest Techniques. For instance, when his family is killed near the beginning, that's Undeserved Misfortune, which is a Rooting Interest Technique. We identify with the climactic Death Star scene because he's in Jeopardy (a Rooting Interest Technique), as are countless others who depend on him.
This scene completes Luke's Character Arc: From not knowing who he is at the start of Episode IV, to knowing he is a Jedi knight. In fact, he makes that shot in the end by relying on his Jedi intuition of The Force, not by using his targeting scanners.
He's able to make that shot because he's got back-up in the form of Han Solo, who is busy completing his own Character Arc. He has gone from being a loner to being willing to be part of an ethical group.
Luke is not there by himself. Not only does he have R2-D2 and Han Solo helping out, but even the disembodied Obi-Wan plays a role. So there's a statement being made about the power of a group to combat evil.
Luke uses The Force to aid in aiming his missile, while Darth Vader, on the Death Star, uses The Force for evil. And so the moment is the culmination of a story full of spiritual undertones which is a Plot Deepening Technique and opposing plot-lines, which is another Plot Deepening Technique.
Luke, using his Jedi powers to aim that missile, represents the rebirth of the Jedi. At the beginning of the film, the Jedi had supposedly all died out, with Darth Vader being their one relic-gone-bad. Obi-Wan had thrown in the towel and was in seclusion. With one shot, Luke revives the Jedi and revives hope.
In summary, we have numerous story-lines converging in this one scene. They belong to:
The convergence of these factors makes Luke's final run to blow up the Death Star anything but simple.
If game designers aren't aware of how such factors work together to create emotionally gripping moments, or aren't able to create such complex and impactful emotionally layered situations, then their games will lose out on countless opportunities to be more emotionally engrossing.