In this mixed-methods study, we examined if students benefitted from a game design course offered during an enrichment hour in terms of gains in their system analysis and design skills. Students at a rural middle school in Southeast US (n = 19) attended a 1-hour game design course offered weekly during an academic enrichment class period, for the duration of a school year, learning basics of digital game-design and practicing system design skills such as making flowcharts. The results of quasi-experimental data indicated that the treatment group's pretest--posttest system analysis and design skills, compared to the control group, which did not receive any training, further improved, F(1,33) = 16.516, p < 0.001. Results from the interviews showed that the participants were able to verbalize how they applied system analysis and design skills developed during the course to problem-solving in different contexts. We discussed the instructional aspects of learning game-design that align with systems thinking. We also explored the possible influence of initial cognitive skills on student learning outcomes from such interventions.