The purpose of this research is to investigate students' learning experiences in a systematic game development process. The study was conducted at a science and arts center, where gifted students can enroll in after-school activities. Fifteen students and one instructor participated in a 12-week problem-solving implementation. During the last five weeks of the process, the students were engaged in developing educational computer games based on a game design model. Our findings showed that the game design model used in the study allowed the students to become aware of professional game development activities, such as identifying a target audience, prototyping, and evaluation. Furthermore, this game design model enabled a more systematic and faster implementation of the game development activity. The results of the research also showed that game development activity yielded important educational outcomes for the students to become skillful at problem-solving and convey their feelings/thoughts to the artifacts through the experience of the design process.