If a girl plays hard to get, not only do I get turned off by the fact that she's into games but I also value my time very much to keep chasing. If I'm being offered on the table, better get me before someone else does. Plain and simple.
You should play hard to get not impossible to get.
Be sure to reward the other person and give in so that the other person knows there is something worth working for. To know that all their hard work will pay off.