(Part 1 is here.) The big difference between soccer and football is the pace–with soccer, play just goes on and on, in a more or less continuous flow. With football, everybody sets up runs a play which takes usually not more than 20 seconds, and then stop and set up to run another play.
This is kind of weird, because if you think of sports as a substitute for war, football is more analogous to 19th-century European warfare, with units being moved carefully into position and then executing maneuvers. Soccer is faster and more anarchic. I wonder how this relates to the fact that soccer is popular in Europe and football is popular in America.
On another note, I think football looks cooler than soccer, largely because of the helmets. (Some people I know think they look stupid, though.) It looks like there are robots out there fighting, as opposed to just guys in shorts and polo shirts.