Harmonix and Red Octane sparked a rhythm game phenomenon with 2005's Guitar Hero and its plastic guitar peripheral. And while the companies should be commended for the expert implementation of a music game controlled with a guitar, they weren't the first to hit upon the idea. Konami's Guitar Freaks series debuted in Japanese arcades and on the PlayStation in 1999. Even though it never saw release in the West, it caused enough of a stir that GameSpot reviewed that first effort and hailed it as an instant classic. The basic gameplay was essentially the same as the Guitar Hero everyone knows, but there were only three buttons instead of five, and markers scrolled up a flat note highway instead of down a three-dimensional one.

Of all these look-alike games, this one has the most tangled web of lawsuits: Red Octane, Harmonix, and Konami all wound up firing patent infringement lawsuits left and right before the toy instrument craze died out. However, none of them were able to declare ultimate victory in their disputes, as all the significant suits between the companies either stalled or were settled out of court.