The application of complex systems theories to the study of narratives proved able to offer a high heuristic value for the analysis of movies [24,26], TV series [35,36], music [45] and different other media with narrative capacity [cf. 20]. However, they were not yet thoroughly employed for the study of video game narratives. To address the relation between formal complexity and the complexity of response in video games, this paper conducts a contrastive analysis of two games of the Halo series, namely Halo 3 [6] and Halo 3 ODST [7]. Formal complexity is analyzed by applying Cutting's [13] approach for counting (narratorial) complexity. The evaluation of the responses to the narratives of these games is based on crowdsourced data, through Hven's [24] and Kiss and Willemsen's [26] understanding of audience response. The findings reveal that a complex response is at least partly predictable through an analysis of the formal quantitative and qualitative/organizational aspects of narratives, and, ultimately, that narrative complexity is a factor in the appreciation of games by the audience. The paper also poses the basis for the identification of a "Goldilocks level of complexity', which can maximize the appreciation of video games stories.