Flashlights Off! – A Left 4 Dead 2 Game Review


By: Amanda Leo, Samantha Stahlke, Rylan Koroluk, and Rina Wehbe


          Left 4 Dead 2 is a cooperative first-person shooter game developed by Valve Corporation and released in 2009. The immense popularity of the Left 4 Dead (L4D) series has inspired  the release of a comic and a large collection of fan-made games and DLC (downloadable content). L4D itself started as a fan-created mod of Half-Life 2, with the development later taken over by Valve. With reviews of 9/10 from IGN.com, 9/10 from GameSpot, 4/5 from Common Sense Media, and 4.5/5 from Metacritic, it is one of the most highly-rated collaborative first-person shooter games of all time. While using the game’s single-player mode is thrilling and features excellent team and enemy AI, many reviewers suggest that the game’s strength is revealed through its multiplayer experience. This has raised the curiosity of what exactly makes Left 4 Dead 2’s multiplayer so enjoyable to play? The HCI Games Group decided to play, analyze, and review the cooperative experience of Left 4 Dead 2.




Social and Psychology Aspect

“Look, my friendly fire is super low.” – Rina

          Currently, the mainstream video game market has no shortage of first person shooters (FPS). Top sellers currently include Destiny, and Call of Duty – titles emblematic of the classic FPS ideal – but also Grand Theft Auto, which is increasingly borrowing from the FPS genre.  The question then becomes: “What makes the L4D series original and competitive?” According to research by Rina R. Wehbe, the answer is simple – Sociality.
          L4D and L4D2 are both cooperative FPS. Cooperative games take advantage of our basic human need to belong. Furthermore, since L4D2 is a team game, players must convince their friends to buy in as well, propagating word-of-mouth advertising and peer pressuring.
          However, not all games that employ cooperative mechanics are successful. The mechanics in L4D increase sociality by fostering collaborative strategy, communication, and altruistic gameplay decisions. L4D2 successfully uses a common enemy to force players to help one another.

          Collaborative strategy. The most basic aspect of cooperative strategy in L4D2 is increased force; your teammates will help you fight hordes of enemies. However, if you believe that you can survive on skill alone, you are very wrong. Specialized enemies have skills that punish teammates who have strayed from the group. Additionally, players will need help if incapacitated by taking damage or falling. These game design decisions force players to stay closer together and depend on each other for help in difficult predicaments.

          Communication. Missions may also prompt player communication by dividing the responsibilities of the team. For example, in the finale of the Dead Center campaign, teammates must retrieve canisters of gasoline and return to a centrally located vehicle. Since the horde is constantly oncoming, players must decide on the most efficient strategy needed to complete the level. Team members may split up based on location, or throw full canisters down to teammates expected to refuel the vehicle, others might be assigned to guard different areas of the map. The complexity of the level increases, as twitch skills, memorization, and gameplay knowledge form only part of the challenge presented in the level; further intricacy is created by causing a social problem stemming from the need to coordinate, communicate, and take either harmonious or leadership roles.

          Altruism. One of the more interesting player dynamics in L4D2 is the altruistic mentality that emerges in response to challenge. The game outwardly encourages altruism by giving players in game notifications and ranking players based on their assistive statistics in the end credits. Additionally, when another player health is low, players are encouraged to donate medicine and heal other players. These features keep players mindful of the cooperative strategies possible. The game may not directly reward cooperative actions, although the end rankings include revivals and friendly fire; these statistics increase awareness of team strategies and dynamics.
          When players are immobilized, a teammate must locate their incapacitated comrade in-game to revive them – often at risk to the player acting as a savior. In some cases, teams can display symmetry-based altruism, wherein players feel that favors are granted equally.
The more interesting situations occur when the ‘savior’ must decide whom to save. Will they employ a calculated altruistic decision based on both player’s previous helpful behaviors towards themselves or will they choose the most skilled player? For example, would you choose Player 1, who has recently revived you, or Player 2, the best zombie killer? Will one of the fallen players encourage the savior to save them, or will they encourage the savior to choose the player that will most benefit the team? Another interesting question to ask is: To what extent will players go to help one another? Does the risk that players are willing to take depend on player actions in-game or their existing social relationship?
          Furthermore, missions such as The Sacrifice require one player to purposefully lose in order for the team to finish the mission. In situations like these, players are forced to be altruistic.

1. Weiten, W. and McCann, D.Psychology Themes and Variations. Nelson, 2012.
2. Alcock, J. (1993). Animal behavior: An evolutionary approach . Sinauer Associates.


Human Players versus Computer Controlled Characters?

          In one of our papers, “Towards Understanding Co-located Gameplay”, soon to be presented at CHI PLAY 2015, London, we discuss the differences between cooperative and competitive play with human or computer-controlled teammates or rivals. One of the main take-aways is that, subjectively, human- versus computer-controlled characters showed some significant differences on measures of arousal and pleasure. However, physiological measures revealed no such differences to objective player experience. Following from this work ,we also sought to test the player’s perceived social condition based on their interpretation of their teammates as computer or human-controlled. Our research shows significant findings based on the game’s design versus the player’s controller. For a complete description of the study and the findings, please keep an eye out for our fully published paper!


Swamp Zombies


Sound and Aesthetics

“I hear dead people.” – Samantha

          Undoubtedly, the core appeal of L4D2 is a combination of situational urgency, diverse weaponry, genuinely petrifying antagonists, and the complex social dynamics afforded by cooperative play. However, the effective combination of these qualities is contingent on their contextualization within a cohesive experience–the creation of a world capable of suspending disbelief. This is where the game’s aesthetic comes in, as a vessel responsible for transforming game events into a believably terrifying sensory experience.
          In common usage, the term “aesthetics” is associated with the appreciation or analysis of beauty, especially in visual art. From a game design perspective, aesthetics is generally defined as the overall feel of a game (a popular model defines aesthetics as stemming from dynamics, which in turn arise from game mechanics in action). At a basic level, game aesthetics are responsible for delivering sensory feedback to the player, traditionally in the form of graphics and sound. (Other forms of output, such as haptic feedback, can also contribute to the player’s sensory experience.)
          While some may see graphics (and to a lesser extent sound) as a distinct, superficial layer pasted atop game mechanics, a successfully designed aesthetic permeates and illuminates the deepest reaches of its underlying system. After all, a game’s creative direction is responsible for representing game mechanics, environments, and characters in a meaningful and understandable way. Together, elements of this direction bring the game from a purely mathematical system to an observable, immersive world. Aesthetics serve as a conveyor of knowledge from the mechanical brain into delicate human consciousness, translating logic into emotion, and event into experience.

          The Undead World. The central theme of the L4D2 world is the ubiquitous zombie apocalypse, incredibly pervasive in modern fiction. Pop culture is laden with the slavering jaws of the undead, as television shows, films, and books replete with tragedy and gore fill the realms of entertainment media. Though L4D2 borrows a number of heavily used creative elements associated with this theme, its execution is incredibly refined, playing upon the expectations of the player to create a thoroughly chilling experience.
          The idle, desolate world glows subtly and sickly from beneath the mild obfuscation of a yellow-tinted lens filter. Eerie silence, but for the occasional creak of a crippled building, or the hiss and crackle of a decommissioned power line. As the player stands in view of a deceivingly tranquil landscape, a string medley straight from a Southern suspense drama echoes in their ear, interspersed with staticky percussion. Suddenly, the drums swell to a military strength, signalling the advancement of the oncoming horde. Under attack, the camera begins to shake, as a cloud of initially subtle scarlet flecks cascades into the player’s eyes.
          Of course, yellow filters, pounding heartbeat effects, flickering fluorescent lights, and any number of other creative entities present in L4D2 have become common, and debatably cliché, within modern zombie entertainment. However, their prevalence is well-reasoned; when exercised in concert, with just the right degree of sensationalism, these elements behave exactly as intended. They leave no uncertainty in spectating minds as to the gravity of the situation. They surround the player in fear, constricting periodically in a symphony of uneasiness, interleaved with suspense and punctuated by terror. They unapologetically drive players forward with a single message, screamed unequivocally over and over: You are in danger.

          An Everlasting Night. Environmental visibility is particularly important within the horror genre, as the presence of darkness fulfills a paradoxical role. It can serve as protector, cloaking the player from danger and masking their location from potential enemies. Conversely, it is often likely to hide a powerful, unseen threat, lurking just beyond reach of the player’s eyesight. L4D2 is particularly effective at practically balancing light and shadow throughout its campaigns, alternating between diverse visibility conditions to stimulate player interest and alertness. In strategic decision-making, light becomes a resource of sorts, equating with knowledge, and often safety. Light can also be dangerous, as it makes the player an easy target, and flashlights can startle dangerous enemies into aggression.
          Artistically speaking, L4D2’s use of light and shadow creates impressive form and contrast within the game’s world. The rapidly shifting shadows of an oncoming wave of foes beneath the underpass has a deeply macabre visual appeal, and a creative eye cannot help but admire the demure beauty in the muted colours of a dying landscape. Even in shade, or strong backlight, well-designed silhouettes convey detailed information regarding the nature of enemies. The imposing spherical form of a Boomer, the hunched, erratic motion of a Jockey, or the lumbering gait of a Charger are instantly recognizable, empowering players to function in an environment that is less than ideal by design. In a world dominated by death, picking up on such cues is essential to survival, as darkness often reigns in the most dangerous of situations.

          Listening to Fear. With unfamiliar surroundings, dilapidated architecture, and the absence of light obscuring the player’s path, exploration frequently yields encounters with creatures unseen until the last moment. This phenomenon gives L4D2’s brilliant sound engineering an opportunity to showcase its practical utility and thrilling implementation. New players quickly find themselves attuned to the distinct utterances of particular enemies, discerning the choking coughs of a Smoker from the guttural expectoration of a Spitter or the sorrowful moans of the Witch. Team communication often references auditory, rather than visual, observations, providing players with the ability to knowledgeably navigate maze-like environments armed with a mental map of their adversaries’ locations.
          L4D2’s sound design gains a degree of uniqueness simply by virtue of its thoughtful integration; auditory feedback is, sadly, oft-neglected in games, dismissed as being of lower importance in comparison with graphical quality. While the average person will rely primarily on visual feedback to become acquainted with their surroundings, games provide a perfect opportunity to explore alternate methods of acquiring environmental information. Depriving players of the comfort and familiarity of omniscient, long-range vision forces them to rely on hearing, and the disquieting experience of effectively tracking or evading an unseen enemy. There is something incredibly primal about this paradigm, robbing players of advanced visual perception in favour of a more primitive and animalistic means of communication. In a world overrun with barbaric undead, this regression is immensely appropriate, causing players to adapt their behaviour in a way that serves to facilitate their belonging in the game’s environment.
          Naturally, music and instrumentation play a key role in immersion as well, drowning out the distractions of everyday life and accentuating L4D2’s overwhelming sense of loneliness and desperation. Through the inclusion of compositions that accurately play upon common cultural expectations, the game is able to convey a shocking range of emotions through music, guiding the player’s journey between moments of intense action. Somehow, certain tracks manage to actually sound as if infected by the miasma of the undead, dripping with belaboured tones of sickness and mourning. This feeling resounds with every other aspect of L4D2’s artistic direction, defining the core immersive and emotional qualities of the game.
          As a complete unit, the L4D2 aesthetic delivers a remarkably realistic and emotionally powerful player experience. Creative elements are thoughtfully integrated with one another in contexts that make sense with the game’s premise and mechanics, enhancing player engagement and immersion. Above all, the aesthetics of L4D2 fulfill their role in defining the feeling of the game with unquestionable efficacy, burdening players with the singular, desperate imperative of survival.




Game and Level Design

“Witches are the worst.” – Rylan

          A veritable horde of zombie apocalypse survival games saturate the modern gaming scene, and with so many possibilities it can be difficult to stand out from the rest. Yet, somehow, Left 4 Dead and its successor, Left 4 Dead 2, are often used as a benchmark when evaluating other games of this genre. The popularity of this series can hardly be attributed to a single factor, but there are some distinct features within these games that do set them apart. Of these factors, the design of the levels is one particularly critical component. Left 4 Dead 2 features 13 playable campaigns that each consist of several smaller story segments traversing a variety of levels. Each of these segments uses several storyline components to provide players with motivation and stepping-stone objectives that help guide players smoothly through the campaign. This, coupled with several strategic gameplay design decisions, can be considered part of why the Left 4 Dead series has demonstrated so much success.
         A key factor in the popularity, and ongoing success of a game, will inevitably rest with its replay value. The replay value of Left 4 Dead is directly tied to its large offering of maps and scenarios combined with an intelligent AI system that ensures no two play sessions are exactly the same. With so many separate levels, it would be impractical to discuss each of them in depth. Instead, it is better to analyze the overarching design decisions and the commonalities that exist between levels.
          It is of great significance to the level design of Left 4 Dead 2 to note that it does not feature any map or radar system, a prominent staple of most first person shooter games. In fact, it is normal for players to become frustrated and potentially lost in games with subpar methods of direction. By omitting this usual feature, it is clear that L4D2 is attempting to foster an enhanced sense of realism. A deeper look into the level design of the game reveals the subtle ways in which L4D2 compensates for the absence of this traditional mechanic. Each level in L4D2 has been artfully designed in such a way as to provide players with an artificial sense of freedom when choosing their route. These potential paths, despite appearing superficially different, will all generally lead to the game’s intended objective. This illusion of choice provides players with a more meaningful and memorable experience. In contrast, when players do not have a choice and are required to follow a specific path, L4D2 employs a subtle style of player direction. Instead of using the somewhat heavy handed “invisible-wall” style of directing players, L4D2 takes pains to guides players through their levels with the clever use of light, darkness, and universally recognizable warning signs. For example, when tasked with the challenge of traversing a burning building, players will instinctively seek out areas with less or no fire, thinner smoke, and indications of escape. Guiding players in this manner is a great way to maintain immersion and prevent players from feeling as if they are being forced to pursue a particular course of action. The levels also compensate for instances where a player does “go the wrong way” by “punishing” them with additional enemies or dangerous terrain, but then almost immediately rewarding them with a powerful weapon or booster item for overcoming that challenge.
          With only a few exceptions, the level design of L4D2 caters to a diverse assortment of play-styles. Players that favour a slower, more methodical approach to a game will find themselves rewarded with additional items and even easter eggs. By comparison, players who enjoy a faster paced game will feel the thrill of escaping a dire situation with haste, and by rushing through objectives, players will expedite their quest to reach the “Safe Rooms” that serve as transitions between level segments. These rooms will always contain a replenishment of ammunition, healing equipment, and other armaments that are necessary after a mad dash through a horde of zombies.
          The level designs of L4D2 also include the strategic placement of certain items in specific locations. This is often done in such a way as to provide players with a gentle hint of how to best handle a certain situation, contributing to the overall learning curve of the game. There are several areas in each level where players will find a carefully placed pipe bomb or Molotov cocktail just before, or just after encountering a group of zombies. This method of teaching allows players to realize in hindsight what would have been an effective strategy for dealing with a recent encounter, or rewards them for handling it correctly by replacing the resource they expended to do so. This style of teaching is paired with a minimally intrusive style of in-game icons that L4D2 uses to direct players to critically important objectives. A combination of prominent, but not distracting, finger pointing icons, messages, and colourfully outlined objects enable players to acquire new knowledge as it becomes necessary in order to survive a new hostile situation.
          It is through the calculated use of these kinds of level design, player direction, and reinforcement that L4D2 manages to foster an incredibly immersive game environment. Further, L4D2’s skillful use of these elements has created a game with sufficient variation as to encourage players to play again and again.


Friends Help!


User experience

“[way ahead of everyone else] Hey guys, I think we’re supposed to go this- OH MY GOD! HELP! HELP! A [insert special infected type here] GOT ME!” – Amanda

          As a game developer, creating a highly-sought after game is dependant on providing a polished and satisfying user experience. During game play, team cooperation was often discussed as the primary positive interaction between players and L4D2. There are many components that go into making a team, which we will review momentarily, but the Oxford Dictionary provides a good starting point in their definition of a team; “Two or more people working together, or a group of players forming one side in a competitive game or sport.” Now, we must dissect the elements that make team play so enjoyable, and how L4D2 amplifies these qualities.
         Communication; it’s a staple of our everyday lives, and essential in maintaining relationships. It forms the basic skills of creating new social connections, and uniting group mindsets. In a team setting, communication is how a group can overcome a challenge, make the most of each other’s skills, and adapt to changing conditions. Within L4D2, the option to speak to your teammates allows for such advantages. One can easily alert everyone else of impending danger, suggest alternate routes to the desired destination, request help, and propose ideas in level completion tactical discussions. Each positive interaction promotes team cohesion, causing players to hold one another in more positive regard. Even when the team suffers a loss, many laughs can be had about miscommunications and unfortunate situations. As a group plays L4D2 for longer, it is hard to ignore the vast improvements in communication among the team.
L4D2 does an incredible job of creating a stimulating and thrilling interactive environment. Often, the game’s sense of urgency during a cooperative match encourages communication, teamwork, and a degree of efficiency in completing the level. Each player is put on edge with the eerie landscapes, sounds, and plainly terrifying zombies of various capabilities. Ultimately, this naturally unites the players by playing on one’s survival instincts, natural imagination, and fear of the almost too-real happenings. A player can easily begin to feel drawn into their character’s situation, inducing stress that can trigger more effective and concise communication. As a whole, there is a natural sense of togetherness among players due to the nature of the game and the challenges it brings.
Each element of the game and of team cohesion hinges on the game’s ability to draw in and challenge players. As reviewed in the sections above, the elements of level design, sound, aesthetics, and even manipulation of player emotion and behaviour are achieved with excellence. The audio draws the player in, training them to recognize the specific cries of each of their various enemies. This increased need of concentration facilitates immersion through the intense player focus. In the same way, the layout of the level changes in terms of where the infected can reside. This variance keeps players on their toes during a level, stressing the need to engage in teamwork and communication. The constant need for attending to the audio and visual stimuli provided by the game expertly pulls the player in, inducing many natural emotional and physiological responses. The adrenaline released in response to the constant  of visceral stimuli is something that consistently boosts team cohesion and provides a feeling of relief as each safe house is reached.
To succeed in L4D2, a group of players must come together and function as a team in order to ‘survive’. This encompases quick and informative communication, positive experiences, mutual trust, knowledge, adaptability, and the ability to work with each person’s strengths/weaknesses. As a whole, these skills are important to succeed in everyday life, but they also make social interactions fun. The real-life edge that L4D2 holds with the presented situations allows for real team building to occur, and as a result, it is one of the best games on the market for cooperative play.



         In conclusion, Left 4 Dead encompasses an excellent balance of many elements contributing to the immense success of its cooperative gameplay. Each area of game development was thought out in excruciating detail, which is strongly reflected in the quality and continuing popularity of the game. Every aspect of the final experience is refined with great care, from the level design, sounds, and aesthetics to the psychological/social responses to the game and how the user experiences each detail of the game. Not only is Left 4 Dead 2 incredibly fun, but it’s motivational to the point that it had gained respect outside the realm of leisurely entertainment. Overall, the HCI Games Group gives Left 4 Dead 2 an 8.5/10 with a high recommendation to try the game.

Flashlights Off! – A Left 4 Dead 2 Game Review

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