Burger King product placement, American Idol cameo, and even post-credits Game
Boy secret code drown out Gunn's «Be Yourself» theme (endlessly and cleverly iterated though it may be).
Some are acquired through Game
Boy Advance connectivity, or an e-Reader or just good old - fashioned
secret codes provided to Tom Nook and some of which can only be obtained with the use of a cheating device, which can unlock them all anyway.