Metallica guitarist Kirk Hammett calls Guitar Hero: Metallica calls the game collaboration a "no brainer" and a "match made in heaven." We know Hammett has played the real guitar, but Guitar Hero?
Once, he has played Guitar Hero once. The reason for this is that he was once "addicted to video games." Hammett adds, "At one point I had to say 'enough.'" So that's what he said.
He has seen other people play it, though, giving him the confidence to state, "I'm pretty knowledgeable about it." I once saw brain surgery on the Discovery Channel, and now, I'm pretty knowledgeable about that. Not that Guitar Hero is brain surgery. It's not.