Gamification involves incorporating elements of online games, such as points, leaderboards, and badges into non-game contexts, in order to improve engagement with both employees and consumers. The main point of this paper is, to sum up, what previous authors investigated in the field of Gamification. An analysis of the literature covering 50 papers from 2011 to 2016 was conducted, using Leximancer software, to determine and shape the main themes and concepts proposed in gamification papers. Answering our research question, "What guidelines may provide to future research, the key themes and concepts found in published scientific papers on gamification?", we conclude that the researchers identified eight themes (gamification; game; use; users; business; points; engagement; learning) and twenty-eight related concepts. The present systematic review contributes to establishing possible guidelines for prospective studies, based on the analyzed papers, considering particularly their 'Conclusions' and on the 'Future research' sections, integrating game design contents in business, learning and education. Further, highlights the usefulness of Leximancer for qualitative content analysis, in this field of research.