This is basically cross between "Say something about the user above you" and "Rate the game collection". You look at a person's game collection and note the genres of games they have. For example you look at my collection and say that I'm a shooter and RPG gamer. Then I see the next person and say that since he has a lot of sports games he's a sports gamer.
Also, don't call the genre based on the quanity of games from that genre. I may have a few racers but I rarely play them. Base it off completion rate, platinums, the game itself, and of course how many of them there are as well.
Oh, and you can say more than one.