I was recently playing guitar hero 3, that has a lot of popular songs, when I noticed Satanic things in it.
There is a skull in the opening of the game, and when I was playing I noticed that 2 characters had Satanic symbols on the strum area. One of them had a pentagram, and another had a hand making the horn sign with an eyeball in it. Not to mention a couple of the dark songs they sneaked in there, one called raining blood. I only played the game because my friends were playing it. I remember at one point the characters were playing in Hell for Satan O_O
I have noticed that even though it has these things in it, people still play it because they think it only deals with rock and roll. They even have some songs to try to make it seem not bad, like a rock version of We Three Kings.
So if you or anyone in your family has this, get rid of it. I have not really played the other guitar heroes but they may have some bad things also.