Runtime Monitoring of Temporal Logic Properties in Infinite Mario Bros. Simon Varvaressos, Dominic Vaillancourt, Sébastien Gaboury, Alexandre Blondin Massé, and Sylvain Hallé ⋆ Laboratoire d’informatique formelle Département d’informatique et de mathématique Université du Québec à Chicoutimi, Canada shalle@acm.org Abstract. We report on the use of runtime monitoring to automatically discover bugs in the execution of video games. In this context, the expected game play is expressed as a set of temporal logic formulæ on sequences of game events. Initial empirical results indicate that, in time, the use of a runtime monitor may greatly speed up the testing phase of a video game under development, by automating the detection of bugs when the game is being played. 1 Introduction The domain of video games is currently booming and is the sector of industry experiencing the fastest growth in the world [9]. A recent Gartner survey revealed that consumer expenses for video games would raise from 67 billion dollars in 2011 to more than 112 billion by the year 2015 [3]. Similar to all computer systems, video games have not been spared from programming errors making their way to the release of a product. For example, in Halo Reach (2010), it is possible for players to go out of the game’s map in some places, allowing them to make actions that would otherwise be forbidden [1]. In late 2011, Nintendo admitted that a bug in the latest release of its Zelda series prevented players from finishing the game when a precise sequence of actions is triggered [2]. It is therefore important for a designer to detect a maximum programming errors as soon as possible during the development phase of a game, since with some systems, it is impossible to correct an error using an update after the product’s release. In any case, software bugs are frustrating for players, costly to game publishers and harmful to their reputation. ⋆ With financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Fonds de recherche Québec – Nature et technologies (FRQNT).