Achilles' Heels

A special weakness that can be exploited to cause defeats easier than can be done by using the other means available.

Many of the more difficult enemies in games can more easily, or in some cases only, be defeated by a special form of attack. These kinds of enemies have Achilles' Heels,special vulnerabilities that players can use to their advantage if they can locate it or gain knowledge about it. More rarely, the avatars or characters under players control have Achilles' Heels and then these need to be protected or kept secret.

Examples

The final boss monster in Half-Life can only be killed by first destroyed a number of crystals in the environment and then hitting a small gem inside its head. In The Legend of Zelda series and the Super Mario series, boss monsters (and some enemies) can usually only be defeated by special actions, such as grabbing hold of the enemies' tail and spinning around rapidly or hitting the enemies' so that it shows a vulnerable spot and then hitting that spot.

The idea of placing your soul or heart in a jar to become unkillable as long as the jar is not destroyed is a common feature in folklore. Both Dungeons & Dragons and GURPS have spells that provide this effect to players or their enemies.

The Mansions of Madness can be said to use Achilles' Heels since the players' controlling investigators do not know the winning condition and all enemies can keep spawning until the condition is revealed.

Using the pattern

Achilles' Heels are most commonly used to make Boss Monsters easier to Overcome. The two main design choices regarding Achilles' Heels are their effects related to normal attacks, what is required to attack the weak point, and how players become aware of the Achilles' Heels.

Three main ways that attacks against Achilles' Heels can affect enemies are: through simply modifying the Damage, through having a special effect (for example stunning or confusing), or through being the only way to cause Damage at all. The two latter can be seen as forms of Privileged Actions. When anyone can attack the Achilles Heel, the only thing required is information about the Achilles Heel, while, if only some players can attack it, the weak point can create the need to fulfill Gain Competence goals or acquire the right Tools. Players can gain awareness of Achilles' Heels through the development of the Narrative Structure, through Clues and Traces in the area the enemy inhabits, or through Experimenting when fighting the enemy. Gaining this information can be a Gain Information goal and Supporting Goal when part of the Narrative Structure, which may in turn require other Supporting Goals to actually be able to use the information, if the Achilles Heel requires a specific form of Tool. Public Information about Achilles' Heels can be used to set the Right Level of Difficulty to a lower level.

Can Be Instantiated By

Invulnerabilities together with Vulnerabilities

Can Be Modulated By

Clues, Cutscenes, Diegetically Outstanding Features, Tools

The design of Achilles' Heels requires the presence of a complete Invulnerability but then makes this incomplete by inserting a Vulnerability - for this reason Achilles' Heels both modulates and is in conflict with Invulnerabilities.

Consequences

The presence of Achilles' Heels is a form of Strategic Knowledge that players can use in Combat. This can be used to provide the Right Level of Difficulty and can motivate Gain Information and Puzzle Solving if the Achilles Heel is not Public Information. As Achilles Heels often require unique forms of attack or more specific uses of ordinary actions, having to perform them gives Varied Gameplay.

The consequences of Achilles' Heels depend greatly one if they belong to an Avatar or Character under a player's control or to his or her Enemies. One of the effect that does however not depend on who has the them is that secret Achilles' Heels, or those that cannot be exploited due to missing Powers or Weapons, are likely to lead to Repeat Domination.

In the case of Enemies that have Achilles' Heels, these provide Challenging Gameplay in that they require players to identify a specific Vulnerability in otherwise invulnerable opponents. Trying to identify the exact nature of the Achilles' Heels is likely to be done through Experimenting or Puzzle Solving.

with Powers or Weapons

Strategic Knowledge, Strategic Planning, Tactical Planning

Can Modulate

Avatars, Boss Monsters, Characters, Combat, Damage, Enemies, Powers, Weapons

Relations

Can Instantiate

Repeat Domination

with Enemies

Challenging Gameplay, Experimenting, Puzzle Solving

with Powers or Weapons

Strategic Knowledge, Strategic Planning, Tactical Planning

Can Modulate

Avatars, Boss Monsters, Characters, Combat, Damage, Enemies, Invulnerabilities, Powers, Weapons

Can Be Instantiated By

Invulnerabilities together with Vulnerabilities

Can Be Modulated By

Clues, Cutscenes, Diegetically Outstanding Features, Tools

Possible Closure Effects

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Potentially Conflicting With

Invulnerabilities

History

An updated version of the pattern Achilles' Heels that was part of the original collection in the book Patterns in Game Design.

Acknowledgements

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