Vocabulary knowledge involves more than knowing word form and meaning; it also requires the ability to recognize and recall these dimensions and to maintain access to them over time. Accordingly, the design of post-instructional practice may influence vocabulary learning and retention. This study compared conventional and mobile-gamified post-instructional tasks in Persian vocabulary learning and four-week retention. A two-group quasi-experimental design was employed. Participants were 53 Iraqi learners of Persian at the pre-intermediate level selected through convenience sampling from two classes; data from 46 participants were available for the delayed analysis. Initial instruction was held constant across groups in terms of instructor, content, and instructional time. The control group completed conventional vocabulary tasks, whereas the experimental group practised the target words using a researcher-developed Mobile Vocabulary Gamification Application. Vocabulary Knowledge Assessment Tests developed by the researchers measured form recognition, meaning recognition, form recall, and meaning recall. Data were analysed using independent-samples t tests, paired-samples t tests, and mixed repeated-measures analysis of variance. The control group obtained higher scores across all four dimensions, although between-group differences were significant only for meaning recall and meaning recognition. Performance declined significantly in both groups at the four-week delayed post-test, while the pattern of change did not differ significantly between groups. Thus, the mobile-gamified tasks used in this study showed no overall advantage over conventional tasks in initial vocabulary performance or retention. The findings highlight the need to examine how active retrieval, word production, instructional feedback, and spaced review could be integrated into gamified vocabulary practice.