The study was conducted for cohering academical achievement of serious game studies as well as for attempting to give directions for interdisciplinary development. The purpose of the study were, first, it provides a rationale for integrating game studies lied scattered into a game study field or game industry. Second, by providing exemplary studies according to categories and by analyzing how those studies have been studied, this study provides a milestone for future researchers who are interested in serious game studies. In the article, the author suggests the extended definition of educational serious game study. The educational serious game study is "the study which investigates educational affordances of game including both explicitly intended designed for education and designed for fun but having implicit educational meanings, through the context of formal educational settings as well as informal environments." The author also researched how extended educational serious game studies have been researched according to four categories; game studies which researched educationally designed serious games, commercial games used for educational fields, educational serious games for informal learning, and those found meanings of games. This study has scholarly significance, especially on game study fields. for delineating game studies, a range of proposed and actual applications of educational serious game are reviewed, guiding directions for future studies.