VanishedOne: From which you might infer (since this is a job ad. rather than part of a formal logic textbook, so the absence of 'iff' isn't significant) that if you're not a passionate gamer with a soft spot for classic titles, you're not being invited to apply. Yet the other quotation indicates that 'familiarity with video games' isn't actually required, merely advantageous.
JMich: Case 1) I can name each and every C64 game, and they hold a special place in my heart. I have no idea what games were released in 2014 or what are the most expected games of 2015.
Case 2) I can make references similar to "The Cake is a lie" for any of the games from 2005 onwards, but I have no idea for games before that.
Case 3) I have played most of the games that were released for DOS and Windows, but have absolutely no clue for any console games.
Familiarity with classics is separate from familiarity with gaming culture.
No, it just doesn't overlap with all gaming culture. But the ad. talks about familiarity and passion, not universal knowledge.
The first part basically says: (Fg & Fc) is a plus. Regardless of whether Fg alone is a plus (not a formal inference, but a sensible one in context), you can infer from the semantics of 'is a plus' that it entails not being a requirement. So one can reasonably infer -R(Fg & Fc) and consequently -R(Fg). But then the ad. turns out to be addressed to passionate gamers, implying R(Fg). The fact that Fg in practice is going to relate to some games rather than all games is irrelevant; nobody would expect otherwise.
At any rate, that's my final word on the matter; I'm not keen enough on formalised logic/semantics to argue it out at length on a gaming forum. ^_^