This research develops a set of serious music games for early childhood children. Through using android system and Flash ActionScript 3.0 on Tablet, the researchers develop gameplay for steady beats, pitch matching, melodic direction, and improvisation on pentatonic scales. The intent of this research is to describe the programming experience, challenges, and problem solving in a music educational gameplay design. To reach the accomplished results, effectiveness, and simplification, the researchers adopted Agile Software Development method. All the involved planners, programmers, and designers are critical developers who coordinate and provide instant feedback reciprocally. This paper presents the technical issues and problem solving for developing such serious music games.