There is a 30 man roster limit. No contact is allowed on the kicker, holder and punter. It is lllegal for a defender to contact the passer's arm, it shall be roughing the QB, even if the ball is tipped. Automatic 1st down plus 10 yard penalty, yardage added to any gain. The ball carrier may not lower his head into a defensive Player.
Spins are legal.
Hurdles of down players are legal. Only authorized persons shall be allowed on the sidelines and field of play. All players must be between the 20-yard lines. Teams must use opposite sidelines. Direct snaps are legal.