<![CDATA[Mastering vocabulary is fundamental to students' success in comprehending narrative texts, yet conventional, drill-based instruction often fails to produce long-lasting lexical knowledge, particularly in vocational English as a Foreign Language (EFL) classrooms. Although gamified learning platforms such as Zep Quiz have shown promise in boosting motivation and retention, previous studies have primarily tested these tools using generic vocabulary lists in ideal conditions. This leaves their effectiveness unclear when vocabulary instruction is tied to a specific genre of text and delivered under authentic classroom constraints, such as limited contact time and scheduling at the end of the day. This study addresses this gap by examining the effect of Zep Quiz on narrative-text vocabulary mastery among tenth grade Marketing students at SMK Negeri 2 Purworejo, using a quasi-experimental non-equivalent control group design. Although hypothesis testing did not confirm a statistically significant effect of Zep Quiz relative to conventional instruction, the experimental class showed a consistent upward trend, whereas the control class declined over the same period. This suggests that there is a genuine, albeit modest, instructional benefit that may have been masked by classroom-level constraints. These findings suggest that the effectiveness of gamified vocabulary tools depends heavily on the conditions of their implementation, such as treatment duration, scheduling and baseline learner equivalence, rather than on the tools themselves. This study extends gamification research beyond generic vocabulary instruction to genre-specific learning in an authentic vocational classroom setting. It also offers teachers considering game-based platforms as part of a sustained instructional strategy a more tempered, practice-relevant perspective.]]>
