I was one of the primary developers on Guitar Hero. It is hard to explain just how weird it was that that game became a massive hit. We had already made a couple of music games that only sold modestly, and expecting people to buy this toy plastic guitar on top of that was borderline ludicrous. I lobbied unsuccessfully to cut multiplayer mode, because what were the chances two people with these guitars were ever going to end up in the same house? We heard stories that retailers loved it when we showed it off to them, but I already worked on multiple games with big buzz and lukewarm sales, so that didn't mean much to me. I was already pleasantly surprised when it became a modest success, much less the monster hit it eventually became.