This research aimed to develop a computer-based game entitled CHEMISTRY ADVENTURE qualified to train students’ characters in Chemistry learning, based on its validity, flexibility, and effectiveness. The research method was Research and Development (R&D) consisting of (1) Define, (2) Design, (3) Develop, and (4) Disseminate. The game validity was got from the assessment of three experts. The flexibility of the game was got from the questionnaire results of experts, teachers, and students after playing the game and the observation results of students’ activities during playing the game. The effectiveness of the game was got from students’ characters and students’ learning outcomes after the instruction.

The results showed that the game validity got for each indicator reached 82-93%, the game flexibility for the ease aspect reached 96% and the attractiveness aspect reached 94.4%, the effectiveness got from the mastery learning classically reached 100% and students’ characters reached 80-90%. Based on these results, it could be concluded that Chemistry Adventure game sufficed the quality to be used as an instructional medium in Hydrocarbon topic of XI grade of senior high school to train students’ characters.