Systematic Review of Gameplay Requirements for Massively Multiplayer Online Games

Advanced Requirements Engineering Draft; 23-5-2014

Systematic review of gameplay requirements for massively multiplayer online games

By James Piggott – S1011162

Abstract This paper carries out a systematic literature review of gameplay requirements by identifying gameplay aspects of Massively Multiplier Online games from publications released between 2004 and 2014. These aspects can be categorized to determine the state of the art regarding MMO’s. Aspects include MMO’s in general, their gameplay requirements, gameplay and player modelling, emergent gameplay, theorycraft and the increasing popularity of free-to-play (freemium) revenue model that is rapidly replacing the older subscription based revenue model. This study hopes to provide an up to date state of all of these fields and provide insight in what might be fruitful avenues of further research in the expanding market of MMO’s.

Keywords Massive Multiplayer Online, gameplay, emergent gameplay, adaptive gameplay, Theorycraft, free-to- play.

Advanced Requirements Engineering Draft; 23-5-2014 1. Introduction This paper hopes to provide a comprehensive study of the gameplay aspects of Massive Multiplayer Online (MMO) games. Their increased popularity has led to an increasing amount of game franchises being used as MMO environments. However, as MMO’s rely considerably on players engaging with each other to create gameplay they can be seen as an entirely new form of digital entertainment compared to traditional single player games that only provide a single narrative. The field of MMO games has further been altered by the relatively new concept of free-to-play or freemium whereby gamers do not need to pay to play the game but instead premium game items and character alterations are charged with micro transactions. Free-to-play is only one such topic that has existed before their introduction with MMO’s but has reached an impulse with the increasing popularity of MMO’s. Other topics include ‘emergent gameplay’, ‘theorycraft’ and player modelling. Below are brief explanations of these concepts to clarify their importance.

Free-To-Play (Freemium), as the term suggests, free-to-play or F2P games are those whereby players do not need to pay money to play as only some exclusive content requires payment. The freemium model is the most common software model for use with MMO. With freemium the player is granted access to a fully functional game but they are required to pay through micro-transactions for additional content such exclusive items, in-game character alterations and in rare cases in-game locations. Free-to-play differs from traditional pay-to-play in which the player needs to pay fully upfront or through a subscription to play the game.

Emergent gameplay is a game design term (Chazerand and Geeroms (2008) that refers to video game mechanics that change according to the player's actions. Emergent gameplay includes a number of relatively simple decisions that a player must make, the sum of which leads to more complex outcomes. A possibility is for players to design their own in-game items thus extending the games life indefinitely. A synonym often used in literature for ‘emergent gameplay’ is ‘expansive gameplay’.

Theorycraft is the mathematical analysis of game mechanics to discover the best strategies and tactics to maximize player effectiveness. It uses tools such as statistics, ability lists, and simulations to analyze strategies. Theorycraft is a term first coined with the game StarCraft whose devoted fans analyzed the game in such detail in order to learn how to play the game in an optimal fashion. For MMO’s theorycraft has become an important source of keeping players committed to playing the game, by offering player statistics a new incentive to play the game is essentially created.

All three of these developments have impacted the development of MMO’s severely and has caused an increasing difference from traditional single player games whereby scripted events offer rarely more than one narrative. This study hopes to identify those gameplay aspects unique to MMO’s and discover what influences development regarding Free-to-play, Theorycraft and Emergent gameplay have on those gameplay aspects.

1.1 Related work People have been playing games since the dawn of civilization. Seay et al. (2004) detail how playing games evolved from playing on tabletops and then slowly through technological development games did

Advanced Requirements Engineering Draft; 23-5-2014 not require the involvement of other people and thus players were able to play against each other from distinct geographical locations. The authors make a distinction between multiplayer games like Counterstrike and MMO games like Everquest by the number of players that are able to play together at once. However their definition hardly defines what an MMO exactly is. They do allude to the fact that MMO’s allow players to commit to complex in-game social structure such as guilds that online games like Counterstrike simply have not implemented.

Meredith et al. (2009) describe MMO’s as games that offer a rich three-dimensional world that is populated by thousands of players. The game world being a fully developed multi-player universe with advanced narrative storylines set within a rich visual and auditory environment. The authors studied the field of MMO’s in 2009 and made an inventory of popular games at the time. Though the top 3 of game has not changed (World of Warcraft, Lineage 1 and 2), of the rest of the 20 games analyzed more than half have either dropped significantly in popularity or have been discontinued altogether. The authors only allude to the complex social structures that players can create, but they do define what they believe are traditional MMO gameplay elements such Player versus Player (PvP) combat, Player versus environment, questing, power levelling and developing skills. This proofs that MMO’s origin are firmly rooted from Role Playing Games (RPG) such as board games and single player RPG’s. Indeed the term MMORPG precedes that of MMO’s which instead denotes other game styles. However, the authors do not mention gameplay aspects unique to MMO’s and suggest that a mix of the aforementioned aspects set in a persistent online environment are what denote a MMO.

1.2 Problem statement The objective of this paper is to provide a comprehensive and structured review of all gameplay aspects of MMO’s and online games. Online games differ from MMO games in that they do not have a persistent world. Online games are extension of single player games by allowing players to engage one another in short duration sessions through the internet. To complicate matters, recently online games have started gathering statistics and use them to disperse in-game items such as weapons thus blurring the distinction between online games and MMO’s.

1.3 Research questions So far research into gameplay has been erratic. Most research focused on topics related to the Social Sciences and the Humanities. The Social Sciences investigated on what motivates players, create social learning theories and explore identity connection between players and their game characters (avatars). Research conducted as part of the Humanities focused on studying game narratives and the gaming sub- culture. Only sporadically have there been attempts at establishing the importance of gameplay, and whether different kinds of gameplay aspects influence player motivation. Game studies can rely on a considerable ‘pre-history’ of study focused on games such as fairground attractions, dioramas, panoramas and amusement arcades. However, those games lack the depth and immersive appeal of video games. This literature study hopes to uncover the latest knowledge that academic research has uncovered related to online gameplay.

Advanced Requirements Engineering Draft; 23-5-2014

The first research question focuses on uncovering what has already been published about gameplay aspects related to online games. The choice of online games as opposed to single player games is because the latter can be considered flawed in that they do not support interaction sought by players.

Question 1; What gameplay aspects have been treated in published research on online games?

The second research question attempts to reach beyond just online games and discover what gameplay aspects are unique to MMO’s. MMO’s are rapidly growing to become the most important game segment in the market, as such it would be vital to uncover if and in what regards they differ from ordinary ‘online games’. Question 2; What gameplay aspects are specific to MMO’s, according to published literature?

One rapidly emerging revenue model for MMO’s is free-to-play; this study tries to uncover what has been published so far regarding gameplay elements of free-to-play MMO’s. Question 3; Do Free-to-play MMO’s use any particular gameplay elements more than others?

2. Research method The stated research questions will be answered by carrying out a systematic literature study. The search for literature sources will focus on the usage of Scopus and Google Scholar. By scanning the abstracts of papers found those not relevant to answering the research questions were excluded. The following inclusion & exclusion criteria were used for filtering the results of publication.

2.1 Inclusions This study includes journal paper and in some cases also conference/workshop papers when there too few results. The scope did not extend to editorials, letter to authors, summaries of discussions and so on. All texts are written in English. Terms such as online games, gameplay, massive multiplayer online, free to play, adaptive gameplay and emergent gameplay were included in the search criteria. The latter term was unknown to the author. It was discovered that many synonyms are used by researchers such as ‘expansive gameplay’.

2.2 Exclusion This study excludes papers that treat a social phenomenon (e.g. young people addiction; development of cognitive skills; life satisfaction) and include gameplay as a sideline such as serious games.

2.3 Process Initially the search for literature sources focused solely on Scopus due to its options to limit results according to certain criteria. During the latter the stages of this research the literature sources were expanded to include Google Scholar for those topics that have been under researched. The search criteria and boundaries for Scopus were: (1) limiting the publications to journal papers instead of conference papers (2) limiting papers to those written in English (3) limitation by publication date between 2004 and 2014 (4) the subject area must either include fields of computer science, social sciences or psychology in order to be relevant for the scope of this research.

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To answer the first research question about gameplay aspects of online games the search criteria was widened by using terms such as "game play" OR gameplay OR playability AND “online games”. The first three keywords denote our primary research topic; by using known synonyms for the term gameplay the search results are not needlessly limited. Searching using the keywords “online games” and gameplay yielded 55 results. The abstracts were then used to exclude papers discussing social media games and non-gameplay aspects.

“game play" OR gameplay or playability Articles found Articles used Scopus 7 1 Expanded Google Scholar numerous 9

“online games” Articles found Articles used Scopus 20 5 Expanded Google Scholar numerous 6

To answer the second research question about gameplay aspects unique to MMO’s the search was expanded to include terms that have only become in general usage only recently. Searching using the term “theorycraft” yielded only one result and as such was a topic of further search using Google Scholar. The other term was “emergent gameplay” which also yielded only one usable result. The synonym commonly used is “expansive gameplay” was also later on used and both were further researched using Google Scholar. However, many articles touch upon the same aspect of emergent gameplay, namely that of player imposed rules such as perma-death and only one described it as part of MMO games.

Emergent and Expansive Articles found Articles used gameplay Scopus 1 1 Expanded Google Scholar numerous 3

Theorycraft Articles found Articles used Scopus 1 1 Expanded Google Scholar 2 2

To answer the third research question about particular gameplay aspects unique to free-to-play games it was anticipated that the number of results would be few as this topic has not been researched much. However the term “free to play” yielded 22 results and 9 when the exclusion factors were applied. Those papers discussing social media games or non-gameplay aspects were excluded.

“Free to play” Articles found Articles used Scopus 9 2 Expanded Google Scholar numerous 0

Advanced Requirements Engineering Draft; 23-5-2014 3. Classification of Literature In this chapter the findings of the literature study are presented. The chapter is divided into 6 paragraphs each describing a part of online games or MMO’s.

3.1 MMO It is necessary as a starting to point out the difference between Online Games and MMO Games. The former are an extension of single player games that allow players to play against other players using an internet connection but lack a persistent world. MMO’s on the other hand don’t have a single player component but use a client-server architecture whereby players (clients) play with each other or against each other in a persistent world designed by the game’s creators.

One important aspect of this distinction is latency (the time it takes for data packets to travel over the internet) and the influence it has on gameplay. If the latency between the client and the server is large enough, the responsiveness of the game to a player’s action decreases, and the player’s performance likely degrades. However, according to Claypool and Claypool (2006) not all player interaction is equally sensitive to latency. They have suggested a taxonomy for gameplay according to two criteria; the precision required to complete an action and the deadline by which the action must be completed. As an example, a game whereby a player has to shoot another player with a precision rifle requires both high precision and precise timing and as such this kind of gameplay is sensitive to latency. On the other hand, gameplay that requires exploration, moving and casting spells are less dependent on precisions and timing. As such it can be confidently concluded that MMO’s should not be overly reliant on high precision and precise deadline gameplay for fear that it would disadvantage some players too much. As Online games lack persistent worlds the consequences of such latency are less severe as players are not dependent on their skills to make further progress, though it would no doubt stifle their enjoyment. Claypool and Claypool conclude that the player perspective can also be influenced by latency in a varying degree of severity. The first-person view where viewers control the character through the eyes of the characters shows a high degree of influence of latency with regards to player performance, the third-person view and the omnipresent view less so. MMO’s can thus negate the effect of latency somewhat by allowing the player to alter the viewpoint perspective.

Advanced Requirements Engineering Draft; 23-5-2014

Figure 1. Claypool and Claypool (2006) latency taxonomy

The study of MMO’s has so far been limited to the proprietary nature of the industry and the need to ensure player privacy (Feng et al, 2007). However, game publishers must be able to characterize their player population so that they can provision sufficient resources to support the game and to update the game in a timely fashion. The popularity of a MMO game follows certain general rules that game designers must be aware off. Player’s quitting the game or ‘churn’ as it is known will increase over the life of a game, if a game does not manage to attract a steady increase in players than there will be a decline in player participation. After the games’ initial release player churn will be relatively low as those players familiar with the game already know they like it after playing the beta release. New content releases over the course of a game’s lifetime will attract new players but will only slightly increase player playtime. One notable exception was the game EVE Online which with its steep learning curve excludes those gamers not willing to play less than average of 20 hours per week. Over time player churn will affect new players relatively more as the experienced players have managed to acquire significant virtual wealth and power, the disparity in abilities often discourages new players from continuing to play. The authors suggest that the time players take to play between sessions is a good indication of when players will quit the game permanently.

3.2 Gameplay From the literature it is difficult to form a consensus on how to exactly define the term gameplay. Most hint that it is about player action in the virtual world but they cannot form a consensus on whether this

Advanced Requirements Engineering Draft; 23-5-2014 action is player driven or that it has been designed by the game’s creators. With MMO’s the topic becomes harder as players interact with a persistent virtual world but their actions shape it as well.

To help academic researchers of games the authors Zagal and Bruckman (2008) describe how they created a wiki based active database of basic gameplay elements. One such gameplay element is ‘To own’ an item. In this case ‘To own’ describes the situation whereby a game character finds an item that they then possess and can manipulate. Such examples are categorized by students working on with database and transforming it into a hierarchy of gameplay elements. Besides a description of each element examples are also given. This research not only hopes to create a game ontology of research but also to have students gain knowledge and common understanding. Previously students would describe games in a fashion similar to how the media review games for consumers, this falls short of academic standards. The project has had some difficulty expressing more technical game aspects such artificial intelligence and player interaction.

Consalvo (2009) states that gameplay cannot be understood by just looking at actions but that the ‘game’ also includes reasons, contexts, justifications and limitations. Only by taking all this into consideration can you analyze where the ‘game’ is and its meaning. Strangely enough cheating behavior can be used to analyze the factors of gameplay as it lays bare player frustrations and limitations. Consalvo concludes that games are not completely separate from real life but they seep into each other. This stands in contradiction with the term ‘Magic Circle’ as defined by Huizinga (1949) which describes a bounded space set apart from real life where we can experience things not normally sanctioned or allowed in life. This criticism of Huizinga stems from the fact that what happens in the game cannot be understood without investigating reasons, justifications and limitations.

Lopes and Bidarra (2011), while examining how to develop an adaptive game world that will create challenges suitable to the players play style defined the game world in five broad categories. Their taxonomy hopes to define on what levels gameplay can be altered to create an engaging game and increase the replay value of such games. Each category can alter the player experience and thus alter the gameplay. These five categories are.

1. The Game world or virtual environment; adaptive game worlds are scarce. Previous results at creating such worlds were met with disapproval from players because of their generic and repetitive game worlds. 2. Mechanics; describes how the game elements work. Examples include running and shooting, a potential adaptive system may provide with aim assistance for the player while they are shooting. 3. Artificial Intelligence; this has traditionally been the most researched topic with regards to adaptive gameplay and has been implemented since the earliest games in one form or another. Recently the focus has been on Non-Player Characters as behavioral adaption is a strong means of displaying intelligent behavior. 4. Narratives; the progression narrative can potentially be adapted to suit the skill level of a player. Games such as the zombie shooter Left 4 Dead which relies on a considerable amount of

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adaptive gameplay uses a technique to generate specific sequences of events, adapted to the pace and behavior of the player. 5. Scenarios/quests; adaptive scenario’s and quests have only recently started to become a target for adaptivity research. Quests describe the flow of events and actions within a game. The topic is closely related to adaptive narratives. However scenarios and quests describe larger areas of the game such as the starting point of an event and the end-goal. Adaptive narrative can be used to decide how many monsters the player will face before they reach the end-goal.

Figure 2. Lopes and Bidarra (2011) adaptive gameplay model

Lopes and Bidarra concede that the process of creating an adaptive game world is impossible without analyzing the players playing the game. They describe how developers can incorporate adaptive game strategies to better suit the player’s game style through player analysis. They have defined two broad categories.

. Offline adaptivity; implies that adjustments are made considering player-dependent data, but prior to initiating any gameplay. Such alterations to the game are traditionally done during the loading stages of a game.

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. Online adaptivity; is the term used by many researchers to describe the ability of a game to adjust to its players in real-time, in-game, as they play.

In the above literature the topic of discussion was to adapt gameplay to increase the player’s experience. For MMO’s this is harder to achieve as a lot relies on cooperative play. However, most MMO’s that follow a scenarios/quest structure do have adaptive quests to better suit the experience level of players. Recent examples are games such as Star Wars: The Old Republic and World of Warcraft, both use techniques whereby player are separated into copies of the game world to allow groups of player play at a difficulty level suitable for all.

Tomai et. al (2012) suggest that these efforts have still not matured into useful procedures. Their research claims that the classic MMO model is slowly being changed from one that is quest-driven and where players share a mostly static world into one whereby the game world adapts to players. One example of such an adaptive game world is Rift, published in 2011 by Trion World. However, the fact that players could freely change the game world also caused players to feel disconnected because there was no strong narrative. As such, due to the experimental nature of many adaptive gameplay aspects it will take a long time before they become mainstream. Snowdon and Oikonomou (2011) describe a randomization system whereby a game world is generated that prevents repetitive gameplay while also adapting the game to suit the player’s ability and play style. Despite taking into account as many factors as possible roughly categorized under: 1. Level generation 2. Context specific gameplay adaption and 3. Dynamic difficulty manipulation, they concede that despite progress such game worlds cannot compete with handcrafted game worlds.

One method to counteract the problems associated with adaptive gameplay is to let the players themselves create the gameplay. With such a system the game designers implement only the basic game rules but let players create the objectives and the manner in which they must be accomplished. This is also known as emergent or expansive gameplay and is discussed in paragraph 4.4

Ducheneaut et al. (2006) in their seminal work on the structure of World of Warcraft (Wow) describe how even popular games such as Wow suffer from a high degree of ‘churn’ or player turnover. Their advice is that game designers need to take into account the structure of the early levels to reduce the abandonment rate. Most MMO’s have a maximum experience level that a game character can reach, at which moment the activities switch from levelling-up to accumulating powerful items and accruing reputation. In a game such as Wow, factions that represent good and evil are separated; they can’t even communicate with each other. The authors of this paper suggest that new players choose the good side because of familiarity from popular culture. Experienced players will choose the evil side for new in- game characters not only to achieve new experiences but also not to be burdened by those inexperienced players. The authors cite that it is important for the game to allow players to build game character that represent their alter egos. For Wow this would be either to choose good or evil side, or game classes such as ‘rogue’ or ‘druid’ and gender. The authors suspect that there are more female game characters than there are female players. They refer to this as ‘identity tourism’. This behavior can be seen as form of emergent gameplay as well. The authors warn that future MMO games will need to incorporate such choices to avoid player ‘churn’.

Advanced Requirements Engineering Draft; 23-5-2014 3.3 Player modelling One aspect of gameplay that has seen a rapid increase in research is player modelling. Through generating such an abstracted view of a player in a game environment it is hoped to allow a computer- controlled characters to adapt to the human opponent’s strength and weaknesses. The purpose is thus to increase the entertainment value for human players through a method whereby every aspect does not have to be anticipated by the original game designers (Bakkes et. al, 2012). There are currently two methods of adapting the game to the player’s behavior model. The first is to adapt the game world and mechanics to the skill of the player while the second is to adapt the in-game Artificial Intelligence to be a better coach, companion or opponent. The literature makes the distinction between player modelling and player profiling. The former focuses on how the player plays the game and is a study of the player’s tactics and playing style. The latter, player profiling, deals with constructing a model of internal traits of the player such as personality and preferences. Both are very active areas of study with player profiling in particular relying heavily on psychologically-verified knowledge.

Bessière et al. (2007) support the fact that players model their avatar to have more favorable attributes than their own self-rated attributes. MMO’s are almost unique in that regard as the avatar designed by players is not only intended to be used for playing the game or narrative but also to interact with other players. They conclude that the avatars represented are more extraverted, conscientious and less neurotic than their real-life selves. Especially those unhappy with their real-life selves thought their avatars were better versions of themselves. As such MMO offer the ability to free players from their social situation. The researchers suggest that there may be evidence that playing with an idealized avatar increases their self-confidence and self-worth.

Steve Cornett (2004) studied whether MMO’s can appeal to a wider audience beyond those familiar with playing games. His research was not optimistic, MMO’s and MMORPG in particular are challenging for those not already familiar with tabletop games such as Dungeons and Dragons or pre-internet Multi- User Dungeons. MMORPS’s have complicated User Interfaces designed to make the live of experienced players easy, a matter made more difficult because new players do not know how to communicate with other players to ask for their advice. Some games do offer help, but flyers with the entire keyboard layout of the game printed on them do not offer the kind of help needed for inexperienced players. As such player modelling shouldn’t focus solely on those already playing the game. To not scare away prospective subscribers publishers should also conduct usability tests with those unfamiliar with the game.

According to Reeves et al. (2009) expert players develop more than just a sense of the terrain but develop a sense of situation that is contingent tactically oriented understanding. This is exemplified by their study of the game Counterstrike with its relatively small game maps that never change. They explain that ‘experts see their activities as gestalts – not as individual actions but holistically as “whatever they are doing”’. This means that player movement, player actions and the events happening in the game are all part of one fluid motion. Players describe this sense as part of total game immersion, it is difficult to describe especially of researcher look at it as a series of separate events. As Counterstrike is an online game but not an MMO with an expansive persistent world it is probable that expert gamers of MMO develop a similar proficiency but based on other factors.

Advanced Requirements Engineering Draft; 23-5-2014 3.4 Emergent or expansive gameplay One type of gameplay that has been frequently discussed as relatively unique to MMO games is ‘emergent gameplay’, which is a game design term that refers to video game mechanics that change according to the player's actions. One specific form of ‘Emergent gameplay’ is perma-death, which forces the player all the way back to the beginning of the game if the character dies even once (Keogh, 2013). Single player games can also have such restrictive rules designed into the game but they are rare. MMO’s frequently force players back to a new starting area without there being any monetary of experience penalty but there are MMO’s that do use the perma-death rules. The result for players abiding by self-made perma-death rules is that it expands the emotional engagements possible with the game.

Emergent or expansive gameplay may in fact be just another viewpoint of MMO gameplay in general. Chazerand and Geeroms (2008) compare online games with football whereby the game suppliers provide the platforms (stadiums) and the agreed rules of the game but it is the players who play it in any manner of cooperation they themselves desire. Their own idiosyncrasies within the limits of the game make up the gameplay. Emergent gameplay can thus be interpreted as a trend towards widening the limits of the game and letting players decide for themselves how they create gameplay. The authors conclude with the idea to expose youths to ICT skills early so they can act as developers of online games and enhance them.

In contrast, one MMO game (Eve Online) deliberately uses a very steep learning curve to weed out those gamers that are considered unsuitable (Paul, 2011b). As new players are struggling with the very elaborate user interface structure and uncertain objectives they are forced into player interaction in order to learn how the game is played. This structure of EVE Online whereby the game tells the player to do something without telling how to do it has created a ‘cottage industry’ of web sites and tools outside of the game where experienced players provide information and act as guides. As some of these tools are considered indispensable part of the game the creators have thus handed ownership of parts of the game to players. The overall effect of the near vertical learning curve is that it forces players to reach out to each other. They are thus making the rules of the game and together shape what it means to play EVE Online instead of pursuing a game experience dictated by its creators.

Nardi and Harris (2006) discovered that play in MMO’s and Wow specifically is characterized by a multiplicity of collaborations. These can range from those that are only very brief to highly organized play such as those found with in-game guilds. Not all situations of gameplay are well suited for organized collaboration but the variety is necessary for the entertainment value and the learning opportunities. This would support the conclusion of Paul (2011b) and his investigation of the near vertical learning curve of EVE Online. Despite the virtues of organized collaborative play in MMO’s players seem to have little problem with spontaneous collaboration. The authors surmise that this is a new form of social relation that is being developed within the context of the internet. The developers of Wow actively encourage collaborative play through creation of asymmetrical classes. With differences between classes such as Shaman and Rogue players are forced into collaborative play for both brief encounters and organized questing. However, other game activities such as practicing professions and the establishment of guilds firmly push gameplay towards organized collaborative play.

Advanced Requirements Engineering Draft; 23-5-2014 3.5 Theorycrafting An extension of emergent gameplay is Theorycrafting. Wenz (2012) describes Theorycraft as ‘a process of reverse engineering, a process of extracting design ‘blue prints’ to understand a technology better, whose design is not accessible’. In this case the design is the game algorithm. Players adopt a scientific approach to learn the underlying rules and limits to better understand the game and maximize gain. The author Christopher Paul (2011a) sees Theorycrafting as a natural extension of emergent gameplay as it allows players to collectively decide what constitutes ‘good’ play. For Paul the analysis of the game’s rules through statistical analysis and mathematical modelling to earn the underlying formulae that governs the game is an attempt to better play the game. The term Theorycrafting originates from the game StarCraft but applies mostly to MMO’s. Theorycrafting has gone so far as data analyses that are posted online so players can adjust their play style. Researchers have questioned whether such a ‘play style moves gamers away from social play practices to a more ‘bare bones’ approach were play engages the inner, instrumental core of the game’s design’. Theorycrafting has been described as a form of meta- gaming as it can be described as a game about a game. Theorycrafters are players who are said to have an understanding of science as finding ‘the truth’ behind a game and develop formula for a truthful and correct understanding of the game mechanics. For those actively involved with Theorycraft are obliged to keep track of a vast amount of information and material published about the game. A perceived downside of Theorycraft is that will create powerful elite within the game and thus exclude beginner players. A further downside of Theorycraft is the advent of automatic gameplay tools that allow players reduce the repetitive aspects of gameplay. However this is seen by many as a form of cheating and is actively disallowed by many game creators. Steinkuehler (2006) concludes that MMO gaming is in essence participation in a discourse that continuously expands and has fuzzy boundaries. The gamer is taking part in a larger learning community whereby Theorycrafting is a necessary ingredient. Theorycrafting is as such a natural extension of emergent gameplay.

3.6 Free-To-Play Park and Lee (2011) define the difference between free-to-play and a subscription based business models as follow, ‘Gamers playing online games in the subscription-based business model pay a monthly fee to the game company for access to its games. In contrast, gamers in the free-to-play business model play the game free of charge, but are required to purchase various game items, including clothing, swords, and guns, if they want to enhance the powers or appearance of their characters.’. Their conclusions are that gamers tend to identify with their game characters and experience real emotions when something happens to their avatars. That said, increased satisfaction with the game does not increase the purchase of game items. The reasons for purchasing game items are based on a different dimension. Those players buying game items can be roughly grouped into two. The first are those that have little experience with the game and seek an automatic level-up to enhance their character competencies and skills. This group is often derided by other players. The second group is those experienced players that seek out exclusive items.

Lin and Sun (2011) discovered that free-to-play gamers can spend up to four times the amount of money on gaming than subscription gamers. They categorize in-game purchasable items as either: functional or instrumental props increase the offensive or defensive power of characters, and decorative or

Advanced Requirements Engineering Draft; 23-5-2014 expressive props for altering character appearances. Such in-game items are considered by many as a possible negative influence on fairness and gameplay immersion. The authors maintain that game creators should try and maintain the ‘magic circle’ as proposed by Johan Huizinga (1949). In this circle it is vital that two factors remain unaffected; the presence of a world independent of the everyday physical world and the preservation of game world order via adherence to game-specific and general gaming rules. Lin and Sun conclude that free-to-play may support experimentation in the game selection process, but it may also amplify indecision on part of the gamers on wanting to focus on one specific game.

4. Discussion

In this section we discuss the most important findings of the literature study and try to answer the research questions.

Question 1; What gameplay aspects have been treated in published research on online games?

Online games are essentially extensions of single player games that allow for cooperative play as well player versus player play. However, online games are played over the internet and as such are susceptible to latency, which is described as the time it takes for information to travel from player’s game clients to the server. Some game genres are more affected by latency than others. First Person Shooters in particular are highly dependent on players performing in-game tasks with high precision and perfect timing. MMO’s by extension suffer from the same latency problems but can make up by allowing more diverse gameplay such as exploring and trading when latency becomes a problem. Online games offer gameplay based on player interaction and cooperation, but designers must take care not to exclude player that are inexperienced. Through player profiling it is possible to adapt the game to suit player experience and prevent repetitive gameplay. Some games also incorporate adaptive game world that allows players to make alterations to allow the game engine to do so. However, such technology is still in its infancy.

Question 2; What gameplay aspects are specific to MMO games, according to published literature?

MMO generally follow quest-driven narratives whereby experience points are collected by players that allow to level up to new denote player skill and experience. These set level of experience can form the basis of rules set in the persistent world of MMO’s to prevent harassment of players less experienced and to exclude less experienced players from disturbing the gameplay of expert players. MMO’s can consists of diverse genres similar to single player games but a basic structure of quest-driven and experience gaining structure is at the heart of MMO’s ever since their inception. Nonetheless the structure is slowly being challenged. One problem with this structure is that inevitably gameplay becomes repetitive or a maximum experience level is reached. Expert players often make up their own challenges and associate rules to continue advancing their in-game characters. This form of gameplay is called emergent gameplay and though not exclusive to MMO’s it has matured within MMO’s due to the nature of the games. Emergent gameplay with single player games consists of little more than a player voluntarily setting rules such as perma-death. Within MMO’s rules can be made infinitely diverse as they

Advanced Requirements Engineering Draft; 23-5-2014 influence other players. Some MMO’s such as Eve Online are built around the concept of emergent gameplay and there is a trend towards allowing more player choices in MMO’s.

Question 3; Do Free-to-play MMO use any particular gameplay elements more than others?

Free-to-play MMO’s are surprisingly similar to those MMO’s that use a subscription model. Early adaptions of freemium were often derided by player for fear that the game required players to pay to win or even to pay to play parts of the game for which there were no alternatives. Neither criticism became reality in any significant degree. Freemium based MMO’s generally adopt a similar experience- level based gameplay as subscription MMO’s. Players paying to rapidly rise through the experience levels are a minority. Instead freemium MMO’s offer the possibility to continue allowing players to explore their in-game characters after they have reached the maximum experience level without having to perform repetitive tasks. As experienced players make more payments for in-game items such as weapons and other character accessories it is possible for a MMO to experiment with a hybrid system of introducing a payment system next to a subscription system before converting completely to free-to- play.

5. Limitations

This literature study excludes research performed on social media games and serious games. Social media games are often little more than glorified chat environments and do not offer the possibility to study the effects of gameplay without analyzing player interaction. Serious games are all too often goal oriented and do no not allow players to make choices beyond those set by the game’s designers.

This study brings together diverse gameplay elements of online games and MMO’s in particular to allow readers to understand them together in context. There are few articles about MMO’s that explicitly try defining a taxonomy of gameplay elements without going into technical details. In fact most knowledge of gameplay elements is about single player games and not about online games or MMO’s. Those articles or research projects that describe gameplay elements often start with elementary gameplay aspects but fail to consider gameplay in a holistic manner as interaction between game and player.

Sadly, some research topics such as about theorycraft, emergent gameplay and free-to-play have few articles because they are relatively new. Success of the Free-to-play business model relies to a large degree on getting players to pay in micro-transactions for enhanced content. There has been relatively little study performed on this rapidly expanding business model and as such it can be considered as an area of research with plenty of ‘low hanging fruit’. All three topics are closely related have a large degree of cross-interaction. The exact nature of their interaction has yet to be defined.

However, many technological pursuits of gameplay may not all be positive. Gameplay that is adaptive to the player skills is championed as an innovation but gamers may also object because of a lack of immersion. Emergent gameplay is highly dependent on players helping each, which only works of players are dedicated to play the game. Those that are not can cause irritation amongst other players.

Advanced Requirements Engineering Draft; 23-5-2014 6. Validity Only those research papers written in English were studied. The market for MMO’s is also large in non- English speaking parts of the world such as Japan, China and South-Korea. However, most article regarding MMO’s, games and gameplay are written in English. It can thus be assumed that this literature study has not missed important papers pertinent to answering the research questions.

7. Conclusion

MMO offer a richer game experience than classic single player games or even online games such as Counterstrike. Both of these types of game lack a persistent world, and though they can be engaging they lack emotional ties because there are few or no consequences within the game. Though players can create their own in-game rules and thus create consequences such rules are far more suitable for MMO’s.

Game designers and publishers have also steadily started mixing classic game design with MMO’s. Many single player games and online games now feature permanent score keeping. With the game results players are often able to unlock new game aspects. As such MMO elements are steadily brought into these classic game designs to prevent players turning towards true MMO’s. As such the player interaction with each other and the persistent world elements comes in degrees; it will be interesting to study and reflect what players prefer.

As the introduction mentioned many aspects of gameplay design have not been thoroughly investigated, as such there numerous interesting lines of inquiry for future researchers. For example latency in MMO’s can be further studied as it was in online games. It would interesting to discover whether players with different degrees of latency play parts of the game differently.

Games with a steep learning curve such as EVE Online also often involve more elements of ‘emergent gameplay’ whereby players create the rules and the gameplay. Game designers more often choose to include such elements to increase appeal for experienced gamers, but what are the influences and experiences for casual gamers? As an extension to such a line of inquiry researchers can investigate whether Free-to-play games are more likely to have ‘emergent gameplay’ elements.

Adaptive gameplay and adaptive game world have been touted as possible remedies against repetitive game experiences with mixed results. Researcher can study whether adaptive gameplay is more suited for games with relatively fewer ‘emergent gameplay’ elements as casual gamers are more likely to prefer the appeal of a strong game narratives. Adaptive gameplay may hamper experienced gamers who may in turn prefer adaptive game worlds which they can alter.

Future research can conclude this line of inquiry with formal verification using gameplay modelling similar to the way processes are modelled in the services industry. Such a result will allow game designers to more accurately tailor their games to the player’s needs.

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