when i was first introduced to marathon, i never actually played it much. my best friend had it on his power mac - a quadra 650, i believe - and i watched him play it on occasion. at the time, i was into wolfenstein 3d and doom, so to me marathon was nothing more than a mac-specific clone. matt actually had marathon 2 and infinity, but only the demo of marathon.
it's kind of funny, looking back, because he had to play it on the smallest size resolution with that "every other line is black" option enabled, it was so slow. a couple years later, matt's dad nuked the computer. since the games had been "borrowed," (heh) he didn't have the cd's, so he lost marathon forever.
the next time i saw marathon was when m2 came out for the pc, and matt got it for me for christmas. he would come over and we would play through the game, taking turns on levels (or whenever one of us died, the other would have a turn at the same level). that was on my parents' packard bell pentium 100, windows 95, 16 mb ram.