Currently, Dementia is a leading cause of disability and dependency among the elderly worldwide. The World Health Organization (WHO) lists it as the seventh largest cause of mortality. Exercise using hands and fingers can be crucial in suppressing the development of dementia. Thus, we are studying an hand gesture exergame system to play video games while doing hand exercises. We have implemented the prototype system. In this paper, we collect four video games and define five hand gestures to control a game. Then, we applied the system to 10 elders in Indonesia to evaluate the applicability where their questionnaire results confirmed it.