<![CDATA[Teamwork is an essential social skill that should be practiced through direct interaction from an early age. However, many educational games remain individually oriented and provide limited opportunities for children to communicate, coordinate, and cooperate toward shared goals. This study developed Zona Penjaga, an online multiplayer educational game that adapts the traditional Bentengan game to facilitate teamwork-oriented learning among elementary school students. The game was developed using the ADDIE model and implemented with Unity, Photon Unity Networking for real-time multiplayer interaction, and Firebase for gameplay data storage. The evaluation involved 15 fourth-grade male students aged 9–10 years from one school in a one-day implementation without a control group. Data were collected through pretest-posttest questionnaires, gameplay observation, black box testing, and the System Usability Scale. All tested feature groups functioned as expected, indicating technical feasibility. The Wilcoxon signed-rank test showed a significant increase in posttest teamwork scores (Z = −3.078, p = 0.002); however, the low N-Gain value (0.21) indicates limited improvement. Observed cooperative behavior during gameplay was high, with a mean score of 3.61 out of 4.00, but this finding reflects short-term teamwork tendencies and in-session behavior rather than long-term skill development. Usability was moderate (SUS = 63.33), and 66.7% of participants scored below 68, indicating the need for substantial interface and onboarding refinement before broader classroom use. Overall, Zona Penjaga is technically promising, but its effectiveness and usability require validation through larger, more diverse, controlled, and longitudinal studies.]]>
