Take a handful of American college football players, line them up, remove the numbers from their jerseys, and I'll probably be able to tell you what position they all play. There is a body type tailor-made for each position in the game. What's so different about the Japanese game is that these differences sort of exist, but they're so heavily muted. With the exception of like two guys, everyone on the field is the same height to within an inch or two, and the linemen are just a little bit more pudgy. One team's running back pretty much looks like both of their OGs. There is not a single guy who looks totally jacked like Ulofoshio or Gaskin or whatever--you can tell these guys don't live in the weight room when not playing.
The sportsmanship is amazing, the wildly erratic release points from the quarterbacks is interesting, the defense being clearly imported from the BIG-12...
It's pretty fun to watch!