Also one last thing, the confirmed balance is the amount of btc in your account that has reached the 6/confirmed state on the bitcoin network, we require this to be able to withdraw the bitcoins.  Unconfirmed is what has been received, you can play with these bitcoins immediately, and doing so may trade with the bank and end up getting your balance confirmed quicker in some cases.

If you are done playing and still have unconfirmed BTC you can either come back later, or you have to wait until the bitcons become confirmed which can take between 5 minutes and 2 hours depending on their current state.