Designing Limes Text: Adapting an Educational Video Game into a Text-Based Format for Controlled Experimental Comparisons

Comparing educational video games and text-based learning presents a significant challenge when trying to ensure a fair comparison between the two formats. Their distinct natures, particularly in terms of engagement and interactivity, introduce uncontrolled variables that are often not directly comparable between a video game and a text. Many prior studies rely on static text conditions that do not account for reader engagement, decision-making, or interaction patterns. This paper therefore proposes a structured game design approach to developing a text-based application that enables a more precise and controlled comparison with video game-based learning. Limes is a 2D educational video game set in Roman frontier Germany, designed to teach historical knowledge through exploration and interactive learning elements. The game features a structured narrative, Codex entries with historical information, and secondary missions, all contributing to the player's engagement and learning experience. The text version of Limes is not a game but replicates key gameplay characteristics in a structured text-based format, providing an alternative to traditional text conditions in experimental research. Unlike passive reading conditions, this Text-app is designed to be interactive and engaging in the same ways as its video game counterpart. Moreover, like the video game, the Text-app tracks player behaviour, such as time spent reading, engagement with Codex entries, and whether secondary mission texts have been read, using a five-star rating system mirroring the game’s assessment mechanics. The present paper discusses the development of the Limes Text-app and presents a game design framework for adapting educational games into experimentally viable text-based counterparts. The contribution is particularly relevant to research on video game effects in education adopting experimental designs. However, beyond its experimental utility, the newly developed text-app offers promising opportunities for other research areas, and we discuss how it can, for example, be used to assess and explore digital traces of learner characteristics and behaviours. To conclude, by ensuring structural comparability and capturing interaction data across formats, the Limes Text-app addresses a key methodological challenge in video game-based learning research: the difficulty of creating valid text-based control conditions that enable meaningful comparisons. While Limes has been developed in the context of history education, the impact is much broader as our design framework is adaptable and could be extended to other domains and narrative-based games.