According to the ESRB, this game contains: Mild Lyrics
Parents might want to get a complete song list and look the lyrics up on the Internet, but other than the occasional word here and there during a song, there's nothing to be concerned about. There's no violence and no sexual content— the game is all about watching notes and playing the guitar.
People who like music games must own this one.
People who don't like music games must own this one. The only reason to not pick this up is if someone has a strong aversion to rock music, and even that person might want to think about it.
Deaf and Hard of Hearing gamers… well, what can I say? The game revolves around playing a mock musical instrument and incorporates huge amounts of auditory input. It's possible to play the game based on visuals alone, but without the music accompanying it, there's really no point. I'm sorry to report it, but people with a hearing impairment are pretty much out of luck.