This can be done in three distinct ways: The most common way to win is by reducing your opponents Life Points to 0
When GameStop started doing it, it was without providing the staff with the necessary training and expertise, and naturally saw them paying woefully low prices, and of course without any of the individual stores having any independence over how it was carried out
This is largely up to the player
The rules of this move state that the opponent must give you a card of their choice from their collection as a gift if its your birthday
But the Alternate Full Art variant is a bigger hit, possibly proving that the notion of a Mewtwo leaping down at you from a skyscraper in the middle of the city is as rad (and terrifying) as it sounds.
Also, if you Special Summon another Monster to the field while you have this one out, you can turn it into a Level Eight which makes it easier to make a Rank Eight XYZ Monster