Playing the game with the guitar controller simulates playing an actual guitar, except it uses five colored "fret buttons" and a "strum bar" instead of frets and strings. The development of Guitar Hero was inspired by Konami's Guitar Freaks video game, which at the time, had not seen much exposure in the North American market; RedOctane, already selling guitar-shaped controllers for imported copies of GuitarFreaks, approached Harmonix about creating a game to use an entirely new Guitar controller. The concept was to have the gameplay of Amplitude with the visuals of Karaoke Revolution, both of which had been developed by Harmonix.[37][38][39][40] The game was met with critical acclaim and received numerous awards for its innovative guitar peripheral and its soundtrack, which comprised 47 playable rock songs (most of which were cover versions of popular songs from artists and bands from the 1960s through modern rock).