What Makes Good AI?
Gaming
Introduction
Whenever people discuss effective AI in video games, three notable examples frequently emerge: the replica soldiers in the original F.E.A.R., the various alien enemies in the Halo series, and the Marines in the original Half-Life game. These games showcase intelligent enemy behaviors and innovative technologies that still influence modern gaming. A common thread linking these titles is their portrayal of aggressive foes that actively pursue and attempt to kill the player, often possessing a substantial amount of health, which allows them to endure longer in encounters. This clever design makes these enemies feel significantly smarter.
Interestingly, during the development of the first Halo game, Bungie conducted a playtest featuring two versions of the game with the identical AI: one with quick-to-die enemies that inflicted low damage, and the other with tougher enemies that dealt more damage and boasted increased health. Players' perception of enemy intelligence significantly increased from 8% to 43% when faced with the more resilient foes. However, aggressive AI does not universally work across all game genres.
In creating Doom 2016, ID Software discovered that having enemies chase players resulted in defensive gameplay, causing players to backpedal continuously. They shifted the enemy AI design to hold their ground rather than relentlessly pursue the player, enabling players to adopt a more offensive approach.
This illustrates that successful AI design must conform to the game's intended experience. For instance, while aggressive AI suits the alien threats in Alien: Isolation, it would be entirely incongruous in Batman: Arkham Asylum! In essence, effective AI transcends merely having enemies that can harm players. Let’s delve into some features and principles that contribute to excellent AI.
Good AI Lets Players Cheat
Well-designed AI often provides players with "cheats," subtly and without players realizing it. For instance, in the Uncharted series, enemies start with a 0% chance to hit when players pop out of cover, giving players a window to fire back. Similarly, in the Far Cry franchise, only a limited number of enemies can shoot at the player simultaneously, increasing their chances of winning. In the Arkham games, enemies are instructed not to turn around during stealth sections, allowing Batman to take them out unnoticed. Though players might not consciously notice these elements, their absence would definitely diminish gameplay experience. The goal is to create a sense of fairness, even if there’s an inherent bias favoring the player.
Good AI Communicates Its Intent
Good AI can effectively communicate its thoughts and reactions to players. This is often achieved through audio clips—known as "barks"—that guards might use to alert fellow enemies to a potential threat. This can also manifest through animations, body language, and game mechanics like vision cones or noise sensors. Developers have found that characters possessing distinct personalities make AI feel more intelligent, allowing players to anticipate their behavior.
For example, characters in games like Pac-Man and Civilization feature unique traits that players quickly learn to recognize. By expressing their capabilities and intentions—such as guards reflecting on opened doors—the AI creates a feedback loop for players to strategize accordingly.
Good AI is Predictable
This concept may seem counterintuitive, but good AI is often predictable. Halo tech lead Chris Butcher stated that the target of AI design is to maintain consistency, allowing players to anticipate reactions. Predictable AI enables players to develop meaningful strategies while navigating the game-world dynamics. For instance, if guards consistently return dropped weapons to storage, players can plan traps around this behavior.
An adept design balances predictable actions with unexpected outcomes—such as in the Halo series where a fledgling grunt consistently runs away, but players can never be sure where it might flee! This predictability presents engaging gameplay, exemplified in a game like Spelunky, where enemies might seem easy until they start appearing in packs, adapting to various situations.
Good AI Interacts with Game Systems
Examples of exceptional AI can be seen where enemies interact creatively with the game world. In Breath of the Wild, an enemy might not solely attack Link but also retrieve weapons, throw their comrades, and react dynamically. This behavior not only implies intelligence but also offers players opportunities to use the environment to their advantage, such as trapping enemies or otherwise manipulating their actions in Prey through cunning tactics.
Good AI Reacts to Player Actions
AI that reacts to player choices forms engaging narrative experiences. For instance, fear-stricken guards in Batman react more radically as players eliminate their comrades. The Shadow of Mordor system exemplifies this by giving randomly generated orc captains names and tracking their encounters with the player. If a player retreats, the orc might recall this action in future encounters, creating a lasting dynamic that enhances immersion.
Good AI Adapts to Player Styles
Another hallmark of quality AI is the ability to adapt based on player behaviors. For example, Metal Gear Solid V features enemies that adjust their strategies, employing night-vision goggles or laying traps, based on player actions. This serves to uproot repetitive gameplay strategies and keeps encounters fresh and engaging.
Good AI Has Its Own Objectives
In some games like Rain World, AI-controlled animals pursue their own goals, engaging in hunts and establishing territories. Similarly, in S.T.A.L.K.E.R.: Shadow of Chernobyl, bandit factions might venture out to execute their own plans. Such AI behaviors could lead to natural events, enriching the gameplay experience further.
Good AI Encompasses Friendly Units
While much focus is placed on clever enemy AI, friendly units should also demonstrate intelligence. Some developers create companion AI that is invulnerable, while others—like in The Last Guardian—design AI that must actively cooperate with the player, enriching gameplay experiences significantly.
Conclusion
The landscape of AI in video games is multifaceted, requiring developers to balance technical prowess with unique design considerations. The overarching goal should be to enhance player engagement and emerge with richer narratives while striking the right balance in AI behavior—whether it be through creating challenging oppositions or designing friendly companions that aid the player.
Keywords
- AI
- Game Design
- Predictability
- Dynamic Interaction
- Player Engagement
- Reactive Behavior
- Companion AI
- Immersion
FAQ
What are some examples of games with good AI?
Some notable examples include F.E.A.R., the Halo series, the original Half-Life game, Uncharted, Metal Gear Solid V, and Shadow of Mordor. Each of these games showcases distinctive AI behaviors that enhance player immersion and engagement.
Why is predictability important in AI design?
Predictability allows players to develop strategies and set intentional goals. When players understand how enemies will react, they can plan attacks and diversions, leading to a more satisfying gameplay experience.
How can AI be made to feel intelligent without making it overly complex?
Good AI can communicate its intentions clearly using voice lines, animation, and body language. This communication, combined with predictable yet nuanced behaviors, allows players to feel engaged without overwhelming them with complexity.
What role does friendly AI play in enhancing gameplay?
Friendly AI can significantly contribute to gameplay by aiding the player in combat or puzzle-solving. Intelligent companions create added layers to the game experience, making the narrative feel richer and more dynamic.
How does AI adapt to player actions in games?
AI can track certain player strategies or patterns and adjust its behavior accordingly. Examples include changing tactics based on the player's frequency of headshots or stealth infiltration tactics, making encounters feel fresh and dynamic.
