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.