This study aims to extend the learning advantages of game-based learning from formal education to informal learning, and to develop a role-playing game (RPG) to help students familiarize themselves with a new school. Several game elements and principles were considered during the design stage, and the tasks were embedded into a macro-context to simulate a virtual campus. A total of 110 junior high school students participated in the experiment, playing the game via two modes, single and peer mode. Overall, the findings showed that most students gave positive feedback on the game design regarding the dimensions of playability, usability, challenge, and gamefulness. Besides, the learners who used the single mode performed better on the post-tests than those who used peer mode. Despite learners in peer mode engaging in discussion and interaction during gameplay, without appropriate collaborative guidance, they may not have been able to achieve the expected learning goals. The study concludes that participation in the game activity captivated the students' learning attention and helped them learn in a more enjoyable way. Furthermore, the use of RPG in informal learning provided the students with opportunities to be exposed to an authentic campus, making it a good way to trigger effective learning through applying learned knowledge to solve the problems in the game. Future research work is also discussed.