Even though it is experimentally known that playing video games causes fatigue, it is difficult to find such quantitative research. It is also known that video game scores improve by repeatedly playing the game. However, the skills acquired by video game players are not clear. This research aims to clarify the elements of fatigue and the skills acquired and improved by playing video games. Fatigue was measured by critical frequency of fusion (CFF). The skilled process associated with video games was measured by using video game scores. Two kinds of video game machines were used. This research confirmed that the CFF of game players decreased linearly after playing the games several times. The scores of video games also increased after playing the games several times. Moreover, game score improvements are described by professing equation in game scores.