This paper reports a design case for a story-driven language learning game called "Arena." "Arena" was developed in the design science tradition, where purpose-built artifacts are used as a springboard for scientific inquiry. As such, "Arena" is a vehicle for designers and researchers to study the effectiveness of story-based games for engaging learners, as well as to explore some of the various challenges that manifest when designing and implementing gameful educational experiences. In this design case, we--myself, as author, and by extension, my design team of 14 undergraduate developers and researchers--report on the theoretical underpinnings of "Arena" and then draw contrasts between these and our experiences as practical designers. The contrasts we note include: (a) second language storytelling as a wicked challenge, (b) managing competing requirements for ease-of-use versus meaningful learning and engagement, (c) making playful connections between play and work, (d) the subtle impact of player point of view, and (e) designing for our target demographic of young male gamers.