Easy. Unlock all other achievement and this will pop. This has to be the easiest Tekken game on Xbox so you will have no trouble at all. The most annoying achievement is the do 50,000 points of damage in practice mode, which I chipped away at with between 1k - 3k each time until I'd gotten all other achievements. I only needed 25k on my final attempt which, using the guide, was done in under 15 minutes.