As an entertainment technology, video games are a popular social activity that can allow for multiple players to cooperatively engage on-screen challenges. Emerging research has found that when people play together, the resulting teamwork can have beneficial impacts on their prosocial orientations after gameplay - especially when the players are cooperative with one another. The present study wanted to expand the scope of these beneficial interpersonal effects by considering both inter- and intrapersonal factors. In an experimental study (N = 115) we manipulated the difficulty of a game (easy or hard) and the behavior of a confederate teammate (supportive or unsupportive playing style). We found that neither coplayer supportiveness nor game difficulty had an effect on the expectations of a teammate's prosocial behavior or one's own prosocial behavior toward the teammate after the game (operationalized as willingness to share small amounts of money with one's teammate after playing). Increased expectations of prosocial behavior from one's teammate were related to one's own prosocial behaviors, independent of our manipulations. Considering these results, we propose alternative theoretical approaches to understanding complex social interactions in video games. Furthermore, we suggest to explore other types of manipulations of game difficulty and cooperation between video game players as well as alternative measures of prosocial behavior.