When the game is set to 49-way joystick in the dip switch settings pressing on the left hand side of the joystick causes the game to freeze, and unfreeze when pressing in the left direction again. This doesn't happen at all when playing with the default 8-way joystick.
再現手順
Go into the games dip switch settings and set it to 49-way joystick if it's not on it already (you'll have to reset the game afterwards if you needed to change the setting, and have it take effect). After the "today's match up" screen the game will start, once there press in the left direction. The game should then freeze, and unfreeze if you press in the direction again. Happens on all 3 bios options.
DIP/入力
blitz - NFLブリッツ (ver 1.21, Dec 5 1997)