There is mixed evidence on the psychological effects of video games. While excessive use can be harmful, moderate use can have emotional, psychological and social benefits, with games successfully used in treating anxiety and depression. More data are required to understand how and for whom these benefits occur. This paper aims to identify correlations between video game genre, player demographics, wellbeing, and the in-play psychological processes for adult players. Adult gamers (n = 2107) completed an anonymous cross-sectional survey canvassing play style, genre, perception of psychological impact and mechanisms (wellbeing, self-determination and flow). A multivariate multiple regression model explored correlations. 88.4% of participants experienced emotional benefits from gaming, with stronger benefits experienced by younger players in all categories. The genres most strongly correlated with psychological benefits were music games, role-playing games and survival horror games. Multiplayer online battle arena games had lower scores for psychological and emotional wellbeing. Certain genres have stronger correlations with beneficial mechanisms, while some may be detrimental to players. These results may guide experimental studies to measure the directionality and strength of these correlations and can also impact practical aspects in development of therapeutic games to treat mental distress.