AFAIK there is no difference in the game itself between the North American / UK versions and the Australian version. With BD the Australian publisher chose to use a different version of Starforce copy protection, but since there is only one English patch for DD that was not the case for that game.
The box should indicate the publisher and possibly the region. North American releases should have an ESRB rating on the box (ie T for Teen), UK releases have a PEGI rating (for BD it is 12+, not sure about DD). I don't know what the Australian rating system is called, but BD got a rating of MA15+.
