This study evaluates the effect of game mechanics by employing serious games and gamification for improving learning outcomes. This is done by considering the performances of the students in terms of the test scores. In the quasi-experimental set-up, which consists of 108 students in their intact three classes attended a series of lessons on sexual health course that was delivered using serious games, gamification, and conventional training elements. The test scores were analysed and compared based on the defined methodology of this paper using SPSS statistical tool version 24. This study found that the students learning outcomes improved after the interventions as the results indicated that there was a statistically significant increase in the test scores from pre-test (M = 24.65, SD = 6.38) to post-test (M = 74.96, SD = 15.89), t(107) = 32.48, p < 0.001 (2-tailed). Also, there were statically significant differences in the mean scores across the three classes of game mechanics in the post-test F(2,105), 71.86, p < 0.001, of which serious game and gamification outperformed conventional training students. Moreover, the overall results demonstrated that there were no substantial statistical significance differences among boys and girls who participated in the serious game and gamification for all tests (p > 0.05). Thus, this study suggests that employing a combination of game elements such as leaderboard, points system, competition, badges, levels, and immediate feedback can serve as a recipe for interactive learning, hence, improves learning outcomes.