"If you try to build emotional scenes in the same way movies do it, you will fail," said Yager's Jorg Friedrich, whose Spec Ops: The Line recently raised the bar for storytelling in shooters, at a packed session at GDC Europe.

The distinction between games and films, he argued, is simple. When you watch characters in films, "we feel with them, because we have time for it," he said. "During a game... we are constantly trying to solve and overcome problems. This changes the way we empathize with characters on screen."

As an example, he pointed to the scene in The Empire Strikes Back where Luke Skywalker finds out Darth Vader is his father, at the height of a pitched battle. It's moving -- but in a game context, you'd be so busy trying to defeat Darth Vader, "instead of sympathizing with Luke, you'd look for a weak spot in Vader's attack pattern."

Good game choices, in contrast, are those such as Heavy Rain's sequence in which main character Ethan Mars is asked to cut off his finger to save his kidnapped son, argued Friedrich. "It doesn't just make you feel with the character; it makes you feel like him."

Dark moments in stories are needed to make the victories matter, he argued. "The death of Aerith is still the number one memorable gaming moment on many game websites," said Friedrich, of 1997's Final Fantasy VII. This is despite the fact that it is a down moment in a game that, like most, is about winning overall. "Did you ever think about how many memorable events are tied to negative emotions?" he asked.

"You need to sometimes break design rules," he said, to involve the player. "Like a punch line of a good joke," he said, a truly meaningful choice "needs the proper framing or it will become stale." You can't break the rules all the time, in other words, but you can do it for effect at the right narrative moment.

Yager's Rules to Break

1. Never let the player choose between bad and worse

"Sometimes there is no good choice," he said, but that's okay -- even good. That's because in real life, "sometimes there is no way out without getting hurt; sometimes there is no way out at all." You can use that to your advantage in games. But these kind of tough decisions "can only work within a narrative context; without that, it's just frustrating," he said. A choice between two crappy loot items is not an important "bad and worse" choice; a choice between two bad possibilities within a game's story is potentially emotionally devastating.

2. The outcome of a choice has to be forecasted

"You can disguise the outcome of a choice if you want the player to become lost, uncertain, and confused," said Friedrich. Just like in real life, when you come home and flip the light switch and the room stays dark, an unexpected effect creates tension for players. When you get it right, "the player will feel a strong tension and need to act," he said. "This will break through the player's strategic thinking." On the other hand, if a light switch is, for example, instead rigged to a mechanism that launches a rocket, it'll feel forced. "It is important it still makes sense and is comprehensible in the context of the game," he said. "If the choice doesn't make sense, players will stop experiencing the story and start playing the system instead."

3. The player's choice needs to be rewarded or punished

"This is a really tricky one; I think all choices should have consequences," said Friedrich. However, most people who say this, he says, are talking about "real gameplay consequences", which "means that all player choices should be followed by some benefit or disadvantages, and I disagree." "Moral decisions that give different in-game rewards disconnect the player by giving them motivations within the game; it's a tactical or strategic decision," he argues. He dislikes games that have dark/light sides with reward mechanics tied to them, such as those in many RPGs, as the players aim for gameplay rewards rather than making real moral choices. In contrast, there's a scene in Spec Ops where one of your squadmates is killed by civilians in retaliation for the destruction of their water supply -- and they come after you next. "The choice can be solved in multiple ways, either by using deadly force or scaring them away; you can solve it so that no civilian is hurt. You can also take revenge," said Friedrich. "We intentionally did not add any rewards to the player choice -- we wanted players to decide for personal reasons. We wanted a moral choice that is not tied to any in-game currency, but plays out only in the player's mind."

Gamasutra is in Cologne, Germany this week covering GDC Europe. For more GDC Europe coverage, visit our official event page. (UBM TechWeb is parent to both Gamasutra and GDC events.)