I've been grading some quizzes over the holiday and love the fact that teaching video game music gives me a chance to learn from the students. I've only played Guitar Hero a few times-- I don't really like music games (probably because I'm playing enough music in real life!). On the quiz, I played a little of Eye of the Tiger from Guitar Hero. Several of the students commented that the mixing was different in the game from what it is in the original song. I'd never thought about that at all, but I definitely agree as I listen to it again, not only are there more sounds added (crowd cheering, clapping, etc), but also the vocals are ducked from the original version. Would this change depending on what instrument you're playing? Probably, but I need to do more research to know for sure.