NFL 2K1 can be played online. And the best thing is, is that when your playing the game online, it flows really smoothly. It doesn't skip like most multiplayer games such as Quake 2 or Unreal Tournament. This one keeps well with in the time frame, However you may need to stop for like 20 seconds for the game to catch up on its lag, but you don't have to do that often. You may notice slight delay, But you must be watching pretty good, because it is very difficult to notice.
Visibility is very good in the online play as well.
It doesn't lack too much of what you'd see in a single player game. The online play should keep you busy for a very long time , its a lot of fun.