I wasn't aware of Koichi Sugiyama's method...very interesting topic that I'd like to look up. Yeah, but everything else you said is on point. A helpful book that I look over--especially for its bibliography/notes--is Karen Collins's "Game Sound: An Introduction to the History, Theory, and Practice of Video Game Music and Sound Design
It's very useful in both realm of of music as well its hardware development.
Proceeding on comparing contrasting game music/film music and discussing functions of music for games: that's definitely an excellent approach to take. I would as well follow a chronological approach to game music, making sure to break each era of focus with its composer and social happenings around that time.
There's plenty more to say...but my focus is a bit fuzzy as having a long day at school. I'll swing by here and drop off more info on a later date.
In regards to a great topic discussion, that context article(s) from OSV would definitely be a kicker to debate about in class. ;)
And just because: http://www.youtube.com/watch?v=xMdwIP9vRWs