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Why Left 4 Dead Works
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Why Left 4 Dead Works

December 21, 2010 Article Start Previous Page 4 of 4

Further adding to the dangers of standing ground or bunkering is the Spitter special Infected. The tall, gangly Spitter launches gobs of stomach acid at players from her jawless face which, on impact, form pools of burning goo at their feet, prompting a quick escape to avoid harm. Tom Leonard explains that this area of denial attack can "quickly force a group of survivors out of a tight spot, or drive a wedge between members of a group," as remaining in the pool results in increasing damage to the player.

Players in an enclosed space such as a room or closely grouped together (at this point, a common rules/skill based behavior versus other types of enemies) are forced to split up and/or move from safety in order to engage the Spitter to prevent her from repeating her attack. This would increase their vulnerability to attacks from common or other special Infected enemies. Like the Charger, the player is pushed to use knowledge based behavior to develop new strategies to deal with the Spitter and the new risks now associated with previously safe areas.

The last new special Infected, called the Jockey, serves as a 'wild card' to the other special Infected. The smallest enemy type in the game, the Jockey resembles a hunchbacked, scrawny man that leaps onto a player and essentially hijacks their controls.

Unless rescued by other players the Jockey will force players away from the safety of their team or location into nearby hazards (such as fire or Spitter acid) or into the range of other special Infected characters.

As a game mechanic, players would have to adjust their previously established rules/skills based behavior to include how to potentially deal with the randomness of a Jockey being included in any interaction with the special Infected or common Infected as game mechanics.

With a total of six special Infected enemy types in L4D2 with abilities to counter a wide variety of player behavior, experienced players of the first game would now have develop new behaviors to deal with the possible encounters or combination of encounters they would have during the course of the games campaigns.


In summary, the use of SRK Framework or similar methods of measuring player's cognitive behavior can assist game designers in identifying weak game mechanics, and help devise improvements or the creation of other complimentary game mechanics.

By recognizing that players were quickly able to learn the properties of the common Infected enemy type in L4D and engage them at rules or skill-based behavior, Valve was able to develop game mechanics in the form of the Special Infected to provide a greater challenge for players through introducing more risks to the easier learned types of skills or rules-based behavior versus Common Infected.

In addition, the special Infected helped reduce the repetitiveness of engaging the Common Infected game mechanic. By providing a means of assessing what constitutes a functional game dynamic at a cognitive level, the SRK framework can help game designers to interpret and apply lessons learned from playtesting and prototypes to improve game play and enhance the quality of the player experience.

In game development, the SRK Framework can be used during the design and testing of game mechanics can help reduce player frustration, as reviewing how players interact and engage a particular mechanic can identify their strengths and weaknesses.

Additionally, using SRK Framework in the cross-examination of a game mechanic's functions might also lead to the development of additional, complimentary mechanics to add more to game play and help reduce feelings of repetitiveness. As evidenced in L4D and L4D2, having a variety of different mechanics that shift players out of familiar skill-based behavior into knowledge-based introduces new challenges for players to overcome and therefore reduce repetitiveness.

Overall, this could lead to higher quality games with strong mechanics which maintain a good balance between challenging the player and retaining a simple and understandable dynamic that supports learning and improvement.

Measurement of player's cognitive behavior can assist game designers in identifying types of player behaviors for use in developing new game mechanics for a sequel or expansion. As the basis for their creation was primarily to counter player behaviors observed in L4D and introduce new challenges and experiences for players to overcome, Valve created the Jockey, Charger and Spitter for L4D2 to bring further variety to special Infected encounters in game and reduce monotony.

These new mechanics helped reduce veteran L4D players' feelings of repetitiveness in experiencing reused game mechanics from the first game as well as adding more content and mechanics for newer players to experience. Recognizing the skill-based and rule-based behaviors that players engage in while playing a game can allow Game designers to introduce new or adjust previously established mechanics either during the development process or in subsequent titles.

The use of such methods not only require veteran players to develop new behaviors to overcome the new challenges but also give newer players a wider variety of complex mechanics to engage, thus enhancing the quality of the gameplay experience for all players.

Article Start Previous Page 4 of 4

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