I just dug out my copies of C64 demos by System and all the source code I could find for stuff I wrote at the time. Most of it is going to be unintelligible unless you've done C64 assembly yourself, but its useful for historical purposes, I guess. All I ask is that you be ignore the poor readability, lack of understanding of the hardware features, self-modifying code, and combination of angst and bravado, both misguided. When you're a teenager (this code ranges from 1992-1998, so I was 12-18) you say stupid things :)
(Shockwave has more stuff that may or may not include stuff by me. Same warning applies).