NFL Blitz is simply the greatest football game ever.
The rules in Blitz takes some liberties with the rules of football, first downs take 30 yds instead of the traditional 10 and there are no penalties whatsoever. overall it's a really great engine that will keep you playing for a long time.
the graphics in Blitz are highly polished, with huge players and awesome looking hits that make for a fantastic looking game that has practically unlimited replay value. the sound is decent, the commentator sucks but the sound of players getting hit are awesome.
Overall, just buy Blitz, don't even rent it, just buy it, you won't be sorry.