I never played Gameplay 99 the only two Games I played that weren't Madden that I enjoyed to the highest of levels was ESPN 2K5 and NFL Blitz 2000. I see some people still are doing Mods with current players in the NFL on ESPN 2K5 especially that is pretty awesome.
I do remember having NFL QB on N64 and that was hard as hell to play with the Buttons for me.