This report discusses the design and development of Wu, a 2D action game intended to serve as a means for exporting Chinese popular culture to Western players. Developed with the Unity engine, the game features a dynamic difficulty system that monitors player behavior and automatically modifies the content to better match the observed level of skill. Feedback from playtesting confirmed that the dynamic difficulty adjustment significantly increased the probability of completing the game, and that most players acquired a better understanding of the Wuxia genre on which the game is based.

Procedural Content Generation (PCG) and Dynamic Difficulty Adjustment (DDA) have been used separately in games to improve player experience. We explore using PCG and DDA together in a feedback loop to keep a player in the "flow zone." The central tenet of this work is a conjecture about how the shape of the performance versus difficulty curve changes at the boundaries of the flow zone. Based on this conjecture, we have developed an algorithm that detects when the player has left the flow zone and appropriately adjusts the difficulty to bring the gameplay back into flow, even as the skill of the player is changing. We developed a game-independent algorithm, implemented our algorithm for the open-source Infinite Mario Bros (IMB) game and conducted a user study that supports the hypothesis that players will enjoy the game more with DDA - PCG algorithm.

Endless runner (ER) is a game genre where the player controls a constantly running character. The player's enjoyment is closely tied to the difficulty of the game, which makes it an interesting platform for dynamic difficulty adjustment (DDA). DDA is a way of balancing game's difficulty by the use of computer-aided adjusting methods. First, we have developed an endless runner type of game using Unity and utilizing client-server architecture. Second, we have implemented a DDA system using player modeling and genetic algorithms. We have tested the validity of our approach on live users. We were able to adjust the game difficulty to increase player enjoyment and reduce player death rates in levels. This approach can be used in a production environment to improve players' enjoyment of endless runner games.

Innovations in computer game interfaces continue to enhance the experience of players. Affective games - those that adapt or incorporate a player’s emotional state - have shown promise in creating exciting and engaging user experiences. However, a dearth of systematic exploration into what types of game elements should adapt to affective state leaves game designers with little guidance on how to incorporate affect into their games. We created an affective game engine, using it to deploy a design probe into how adapting the player’s abilities, the enemy’s abilities, or variables in the environment affects player performance and experience. Our results suggest that affectively adapting games can increase player arousal. Furthermore, we suggest that reducing challenge by adapting non-player characters is a worse design choice than giving players the tools that they need (through enhancing player abilities or a supportive environment) to master greater challenges.

Games are irritating when they are too hard, and boring when they are too easy. Level Eight is a game development company which is, during this project, developing an endless runner. This thesis describes research and implementation of a dynamic difficulty adjustment system in Level Eights’ endless runner by considering several conditions of the player. This was accomplished with the help of the game environment by implementing procedural content generation and combine it with the dynamic difficulty adjustment system. / Spel är irriterande när de är för svåra, och tråkiga när de är för lätta. Level Eight är ett spelutvecklingsföretag som under detta projekt utvecklar ett ändlöst löparspel. Denna avhandling beskriver forskning och genomförande av ett dynamiskt svårighets justeringssystem i Level Eights ändlöst löparspel genom att överväga flera villkor för spelaren. Detta uppnåddes med hjälp av spelmiljön genom att implementera procedurell innehållsgenerering och kombinera den med det dynamiska svårighets justering systemet.