And that old man is me. I played Halo for a little while when my friend rented it and brought over his Xbox. We played co-op, and liked it, then never played it again for some reason. This was back when Halo was about the only game for the Xbox (like Super Mario 64 for the N64) and no one knew just how much it would blow up. I largely ignored it since I was a Nintendo/PSX man. Until now, when I bought it for $20 (too high in my opinion), grabbed a Mountain Dew margarita, and sat down to figure out what everyone was talking about. The most satisfying…