The aim of this article is to present V.E.Ga.S tool, which intends to classify video games, study their nature and to corroborate hypothesis by a pragmatic approach. The approach has been inspired by the methodology of Vladimir Propp, who has classified Russian Tales at the time, as well as on the works and the "iterative" approach of the game designers Katie Salen and Eric Zimmerman. The approach consists in studying a significant number of video games in order to index their composition of elementary "bricks". Basing our study on this "bricks" and crossing them with other fields, we will try to classify and study video games. We thus hope to be able to have at our disposal, elements which will contribute to the research of the "emerging discipline of Game design".