to tell static stories in which how a given character will react to players is entirely pre-
determined, regardless of the game-world actions or how the players treat that
particular character. While designers often strive to keep the battles and action
sequences as dynamic and unpredictable as possible, they almost always want to keep
the stories exactly the same every time the players experience them. Why not have
players be able to affect the mood of the different NPCs they encounter? Maybe if play-
ers say all the right things and do not ask questions about sensitive subjects, the NPC
becomes friendly toward the player character. Maybe players can only coax crucial
information out of a character after first becoming his friend. Perhaps the players’ repu-
tations precede them, where the actions players have performed elsewhere in the
world directly impact how that NPC will treat the player character. If players have per-
formed less-than-good actions earlier in the game, maybe the players have to redeem
themselves in the eyes of a character before they can proceed in the game.
In my gameThe Suffering, players determine what ending they get based on how
they treat the friendly human characters they meet in the game. Players have the
option to help these AI-controlled humans, kill them, or ignore them completely. I
deliberately made the characters a wide variety of personalities, and made their AI
reflect these traits. One character is extremely frightened by the creatures in the
game-world, and thus spends most of his time frantically fleeing from them. Later in
the game, players meet a corrections officer named Ernesto who hates all inmates,
including the player character, Torque. When they first meet in the game-world,
Ernesto immediately threatens Torque, pointing his machine gun at him but not firing
it. If players shoot Ernesto early in this encounter, Ernesto will immediately become
hostile to Torque. If players wait, however, Ernesto realizes that he and Torque must
work together to survive against the monsters. Now if Ernesto is shot by players, he
does not immediately become hostile but instead warns Torque that he needs to watch
what he is doing. Thus Ernesto’s AI changes based on how he is feeling about Torque.
Of course, if Torque shoots him two more times, Ernesto will still become hostile; he’s
no fool. In the end it is to the players’ advantage to keep Ernesto around, as his AI is set
Chapter 9: Artificial Intelligence 161
InThe Suffering, the AI
for the companion NPCs
changed their behavior
based on the actions of
the player character.