This thesis studies a few established design principles which were implemented in a developed fast-action puzzle game prototype. The aim was to study how several design principles affected the performance of players. The prototype was described as a Time-Based Memory Mashup with six different ”presets” based on the established design principles in which small changes occur. All participants in the study played through all six presets. Gameplay data was gathered from the participating users and were automatically recorded into a database in order to determine which preset was the most successful. Participants also filled in a survey to answer questions regarding on how they would judge their own performance, engagement and enjoyment of each played preset. Collected gameplay data from the participants were compared and ranked to determine which presets and design principles were the most effective. Surveys, observations and interviews have been studied to see if it matched the statistical data. Participants had higher performances with a fixed or more forgiving timer, which participants preferred the most. Downgraded graphics and sound were enjoyed the least, however did not led to much worse performances. An increased difficulty had the most effect in lowering performances. Design principles such as Pacing, Difficulty, Feedback, Interface Design and Foreground had the most potential to lower performances among participants.

Believable Non-Player Characters (NPCs) help motivate player engagement with narrative-driven games. An important aspect of believable characters is their contextually-relevant reactions to changing situations, which emotion often drives in humans. Therefore, giving NPCs "emotion" should enhance their believability. For adoption in industry, it is important to create processes for developing tools to build NPCs "with emotion" that fit with current development practices. Psychological validity—the grounding in affective science—is a necessary quality for plausible emotion-driven NPC behaviours. Computational Models of Emotion (CMEs) are one solution because they use at least one affective theory/model in their design. However, CME development tends to be insufficiently documented such that its processes seem unsystematic and poorly defined. This makes it difficult to reuse a CME’s components, extend or scale them, or compare it to other CMEs. This work draws from software engineering to propose three methods for acknowledging and limiting subjectivity in CME development to improve their reusability, maintainability, and verifiability: a systematic, document analysis-based methodology for choosing a CME’s underlying affective theories/models using its high-level design goals and design scope, which critically influence a CME’s functional requirements; an approach for transforming natural language descriptions of affective theories into a type-based formal model using an intermediate, second natural language description refining the original descriptions and showing where and what assumptions informed the formalization; and a literary character analysis-based methodology for developing acceptance test cases with known believable characters from professionally-crafted stories that do not rely on specific CME designs. Development of EMgine, a game development CME for generating NPC emotions, shows these methods in practice. / Dissertation / Doctor of Philosophy (PhD) / Video games can deeply engage players using characters that appear to have emotionally-driven behaviours. One way that developers encode and carry knowledge between projects is by creating development tools, allowing them to focus on how they use that knowledge and create new knowledge. This work draws from software engineering to propose three methods for creating development tools for game characters “with emotion”: a process for analyzing academic emotion literature so that the tool’s functions are plausible with respect to real-life emotion; a process for translating academic emotion literature into mathematical notation; and a process for creating tests to evaluate these kinds of development tools using narrative characters. The development of an example tool for creating game characters "with emotion", EMgine, demonstrates these methods and serves as an example of good development practices.

Gaming, a widely adopted form of entertainment, brings out different reactions inpeople. While some perceive it as a leisure activity, other find it the element of violence that can be found troubling. Researchers have found that video games are associated with many advantages such as enhancing focus, multitasking ability and working memory. Educational games aim to create motivated learners, which can be described as enthusiastic, focused and engaged. To create motivated learners, it is important to stimulate players both through functionality and graphical design, as a poor graphical design can lead to unwillingness to continue playing. Therefore, it is important to conduct a thorough investigation on the impact of the user interface on user engagement in order to gain a comprehensive understanding. Previous research has highlighted the importance of extrinsic and intrinsic objectives, as well as the role of activities and emotions in player engagement. Moreover, the collective findings from previous research significantly enhance our understanding of player engagement and its importance in game design and educational settings. However, our research aims to specifically investigate the impact of user interface on user engagement and aim to contribute to the existing understanding in this specific area. This study focuses on addressing the issue of inadequate user engagement in the game SocioBalance. To do this, data on players' feedback of the user interface is collected to understand the source for its shortcomings and identify areas for improvement and subsequently update the user interface of the game. Players were invited to participate in a playtest session and a dedicated questionnaire is administered to gather feedback on the user interface. The findings indicated that by improving the user interface enhanced the clarity of the game's objective. Furthermore, a higher proportion of players found the game to be more appealing. In addition, there was an observed increase in the overall graphical experience and players' inclination to continue playing / Spel, är en allmänt accepterad form av underhållning, väcker diverse reaktioner hos människor. Vissa ser det som en fritidssysselsättning, medan andra anser att våldselement är oroande. Forskare har funnit att videospel är förknippade med många fördelar, exempelvis förbättrad fokus, förmåga att hantera flera uppgifter samtidigt och arbetsminne. Pedagogiska spel syftar till att skapa motiverade elever, vilket kan beskrivas som entusiastiska, fokuserade och engagerade. För att skapa motiverade elever är det viktigt att stimulera spelarna både genom funktionalitet och grafisk design, eftersom en dålig grafisk design kan leda till ovilja att fortsätta spela. På grund av detta är det viktigt att genomföra en noggrann undersökning av användargränssnittets inverkan på användarnas engagement för att få en omfattande förståelse. Tidigare forskning har framhävt vikten av extrinsiska och intrinsiska mål, samt rollen av aktiviteter och känslor för spelarnas engagemang. Dessutom förbättrar de samlade resultaten från tidigare forskning vår förståelse av spelarens engagemang och dess betydelse för speldesign och utbildningsmiljöer. Vårt forskningsprojekt syftar dock specifikt till att undersöka användargränssnittets inverkan på spelarnas engagemang och bidra till den befintliga kunskapen inom detta område. Denna forskningsstudie fokuserar på att adressera problemet gällande otillräckligt spelarengagemang i spelet SocioBalance. För att åstadkomma detta insamlades data angående spelarnas återkoppling på användargränssnittet för att förstå orsakerna för brister och för att identifiera potentiella förbättringsområden, varpå uppdaterades användargränssnittet. Spelare bjöds in för att delta i ett speltest och en speciell enkät användes för att samla in spelarnas synpunkter gällande användargränssnittet. Resultaten visade att förbättringar i användargränssnittet gjorde spelets mål tydligare, dessutom ansåg en större andel av spelarna att spelet var mer attraktivt. Vidare noterades en påtaglig förbättring av den övergripande grafiska upplevelsen samt en betydande ökning i spelarnas benägenhet att fortsätta engagera sig i spelet.

Background. As video games increase in popularity and more people look to them as their primary source of entertainment, discussions around how they can affect players’ engagement become more important. One such discussion is around player agency, a player’s sense of control over the games that they play. Within this discussion, a new type of thinking regarding player agency has started emerging, where it gets divided into the amount of control a player experiences and the amount of control that they actually have. One way to see the difference between the two types of player agency is to look at linear and branching narratives. In a branching narrative, the player’s choices dictate the flow of the story, while in a linear narrative, the player chooses how to react, but the story itself is unaffected. Objectives. Our objective with this study was to explore how player engagement differs between a linear narrative and a branching narrative, and if there is a difference when going from one to the other. Methods. This was done by creating a game demo that contains both a linear narrative, as well as a branching narrative and conducting a user study where participants played the game and answered a questionnaire on their experience. Results. In our findings, no significant difference in engagement was observed through Pearson’s chi-square tests between the different narratives. However, there was a significant difference based on what order the narratives were presented. Participants that played the linear narrative first had significantly higher engagement levels than the participants that played the branching narrative first. Conclusions. We conclude that more research should be made, but we find there is a positive effect on engagement when both a linear and branching narrative presented in the same experience, and the linear narrative is presented first.

Matchmaking is an essential part of many modern online multiplayer games and is used by game developers to give the players the best possible online gaming experience. However, since video games have become more complex, traditional matchmaking systems like TrueSkill have reached their limits in predicting match outcomes. An extensive literature survey on engagement and balance in video games as well as an analysis of Battlefield 4 player data showed that balance can have a significant impact on player engagement. This lays the basis for the new matchmaking approach that is presented in this thesis. It is developed for the online First Person Shooter game Battlefield 4, with the goal of increasing player engagement by balancing online multiplayer matches. The developed matchmaking system is based on regression models, which use player performance metrics to predict the balance of online multiplayer matches. The experimental evaluations of the developed models show that the quality of the prediction results are influenced by the complexity of the different game modes available in Battlefield 4. Furthermore the historical Battlefield 4 game report data, which is used for building the predictive models, shows that this complexity as well as imbalances in the game design add significant noise to balance predictions. Both evaluated regression models – Linear Regression and Multivariate Adaptive Regression Splines – showed similar prediction errors within statistically expected deviation. Additionally it is shown that both methods have significantly smaller errors than the TrueSkill system, when predicting the outcome of games in Team Death Match or Conquest mode. The features that resulted in the lowest errors are commonly used in online First Person Shooter games. Hence the findings of this thesis can not only improve the matchmaking of Battlefield 4, but also benefit other video games of the same genre. / Matchmaking är en viktig del av många onlinespel och används av spelutvecklare för att ge spelare en bättre spelupplevelse. På senare tid har spelen blivit mer komplexa och traditionella matchmakingsystem som TrueSkill klarar inte längre förutse utfall av matcher. Andra studier som avhandlar spelaktivitet och balans i matcher visar att spelare har ökad aktivitet om deras matcher har varit jämna. Det går även att dra samma slutsatser från speldata i Battlefield 4. Syftet med denna uppsats är att utveckla och utvärdera en ny modell för matchmaking i spelet Battlefield 4 som medför bättre balans i matcher och därmed ökar spelaktiviteten. Den utvecklade matchmaking-modellen baseras på regressionmodeller som använder historiska speldata för enskilda spelare för att förutse jämnheten i matcher. Utvärderingen av den utvecklade modellen visar att förmågan att förutse matcher beror på hur hur komplext spelläget i Battlefield 4 är. Det framgår också efter att ha tittat på historiska spelrapporter att förutom komplexiteten i spelläget så påverkar också obalans i speldesignen förmågan att förutse matcher. Båda utvärderade regressionsmodeller – linjär regression och Multivariate Adaptive Regression Splines – har liknande förmåga att förutse utfallet av matcher där ingen är signifikant bättre än den andra. Dessutom visas att båda modellerna förutser matchresultaten för spellägena Team Death Match och Conquest signifikant bättre än TrueSkill. De här spellägena är vanliga i denna typen av spel så resultaten i denna uppsats är inte isolerade till Battlefield 4 utan går att applicera på många spel i samma genre.

Creative Project Abstract: The creative project of this thesis is a script prototype for Underland, a crime drama video game and digital playable story that demonstrates writing and design methods for negotiating narrative and player agency. The story is set in October 2006 and players are investigative psychologists given access to a secure police server and tasked with analysing evidence related to two linked murders that have resulted in the arrest of journalist Silvi Moore. The aim is to uncover what happened and why by analysing Silvi’s flat, calendar of events, emails, texts, photos, voicemail, call log, 999 call, a map of the city of Plymouth and a crime scene. It is a combination of story exploration game and digital epistolary fiction that is structured via an authored fabula and dynamic syuzhet and uses the Internal-Exploratory and Internal-Ontological interactive modes to negotiate narrative and player agency. Its use of this structure and these modes shows how playable stories are uniquely positioned to deliver self-directed and empathetic emotional immersion simultaneously. The story is told in a mixture of enacted, embedded, evoked, environmental and epistolary narrative, the combination of which contributes new knowledge on how writers can use mystery, suspense and dramatic irony in playable stories. The interactive script prototype is accessible at underlandgame.com and is a means to represent how the final game is intended to be experienced by players. Thesis Abstract: This thesis considers writing and design methods for playable stories that negotiate narrative and player agency. By approaching the topic through the lens of creative writing practice, it seeks to fill a gap in the literature related to the execution of interactive and narrative devices as a practitioner. Chapter 1 defines the key terms for understanding the field and surveys the academic and theoretical debate to identify the challenges and opportunities for writers and creators. In this it departs from the dominant vision of the future of digital playable stories as the ‘holodeck,’ a simulated reality players can enter and manipulate and that shapes around them as story protagonists. Building on narratological theory it contributes a new term—the dynamic syuzhet—to express an alternate negotiation of narrative and player agency within current technological realities. Three further terms—the authored fabula, fixed syuzhet and improvised fabula—are also contributed as means to compare and contrast the narrative structures and affordances available to writers of live, digital and live-digital hybrid work. Chapter 2 conducts a qualitative analysis of digital, live and live-digital playable stories, released 2010–2016, and combines this with insights gained from primary interviews with their writers and creators to identify the techniques at work and their implications for narrative and player agency. This analysis contributes new knowledge to writing and design approaches in four interactive modes—Internal-Ontological, Internal-Exploratory, External-Ontological and External-Exploratory—that impact on where players are positioned in the work and how the experiential narrative unfolds. Chapter 3 shows how the knowledge developed through academic research informed the creation of a new playable story, Underland; as well as how the creative practice informed the academic research. Underland provides a means to demonstrate how making players protagonists of the experience, rather than of the story, enables the coupling of self-directed and empathetic emotional immersion in a way uniquely available to digital playable stories. It further shows how this negotiation of narrative and player agency can use a combination of enacted, embedded, evoked, environmental and epistolary narrative to employ dramatic irony in a new way. These findings demonstrate ways playable stories can be written and designed to deliver the ‘traditional’ pleasure of narrative and the ‘newer’ pleasure of player agency without sacrificing either.