They ship the game to the store you designate, and you pay for it there. You don't pay any shipping, but you'll have to pay the sales tax depending on what state you're in.
I usually use it to pre-order a game, since doing it this way avoids giving the in-store people the usual 5 dollars for...
The West LA store on Venice and Overland.
And on the game, I really only think that it is harder because of the Wii controls. When you combine the motion sensor controls of the basic functions (such as hovering in the parachute suit, or manipulating the see-saws, or even lifting and carrying...
Almost every major retailer will ask if what you are buying is a gift, and give you a gift receipt in addition to the normal receipt (Target, for example, will just print it out without even asking). If the person does not like the gift, then they can return it for the credit.