The purpose of this study is to investigate the effect of Malaysian "Kimia" (Chemistry) Digital Games (MyKimDG) module on students' achievement and motivation in chemistry as well as 21st century skills. Chemistry education in Malaysia should put greater emphasis on combination of cognitive, sociocultural and motivational aspects to ensure that students are well-equipped with knowledge, skills and values relevant to the new global economy. Previous studies have reported that digital game-based learning (DGBL) provides opportunities for increasing students' motivation in learning while enhancing their academic achievement and 21st century skills. Based on the DGBL approach as well as constructivist-constructionist learning theories, MyKimDG was developed as a mechanism for achieving the desired goals. In this study, students were provided opportunities to take on the role of game designers, developing digital games while learning chemistry. This study employed quasi-experimental with non-equivalent control group pretest-posttest control group design. Subjects were composed of 138 secondary students. Results showed that the treatment group outperformed the control group in the chemistry achievement test. In addition, students' self-efficacy and high productivity scores improved significantly between pretest and posttest for treatment group. The findings imply that the inclusion of student as game designer approach in chemistry learning is able to help students develop an in-depth knowledge on chemistry and foster their 21st century skills as well as increase students' motivation in chemistry.