Julia Brich, Katja Rogers, Julian Frommel, Martin Weidhaas, Adrian Brückner, Sarah Mirabile, Tamara Dorn, Valentin Riemer, Claudia Schrader, and Michael Weber. 2017. LiverDefense: how to employ a tower defense game as a customisable research tool. In Vis. Comput. 33, 4: 429–442. doi:10.1007/s00371-016-1314-0
In game-related research, it is often necessary to create different versions of a game prototype and gather information about players. To make this possible even for non-programmers, we present LiverDefense, an educational Tower Defense game about the basic functions of the human liver, which can be used as a customisable research tool. LiverDefense can be customised via human-readable XML files both in its degree of difficulty and the content of Likert scale questionnaires to be presented to the player. As a proof of concept, LiverDefense has been successfully employed in a psychological study focused on exploring the effect of perceived control over gameplay on players' emotions. We report on the analysis of this study with regard to enjoyment and frustration and the resulting insights on using LiverDefense as a customisable research tool.