Players usually look mediocre. They are not the hottest or the ugliest in conventional terms.
Sluts pretend to be proud of flirting with many people, having lots of sex but they may actually be very ashamed of it. They may flirt, giving the impression that they enjoy anything and everything sexual but in fact they might just be faking it. They think being slutty makes them stronger. They think it shows that they don't care about what people think. But they do. The harder they try, the more they care.
Both have low confidence. People with high confidence won't need to flirt that much/get that many gfs/bfs to boost the confidence they are missing. They will respect themselves and others more than lower themselves down to such cheap level. Yes, most people won't agree with me (about players and sluts having low confidence), but that's just my view. You don't have to agree with me.