The small roster really hurt this one. You'd be much better off with Fatal Fury Special.
The game only features 6 playable characters (unless you use cheat codes) and they all tire pretty quick. The single player is fun, for the first time. It gets old really quick, and maybe thats why there are so few characters. Actually, 6 is an okay amount of players for the one player campaign, but in multi-player, everybody's been chosen after a couple of fights. That's just lame.
The gameplay in Fatal Fury is basically the same as the original. Not a whole lot of difference there. The graphics are pretty good, all of the character sprites look nice. The levels are alot better though, and they really help the game out. The sound is what you'd expect from a SNES fighter.
There's not awhole lot of replay value in FF2, mainly because of the small amount of characters. You just get bored of them eventually. Overall, I think Fatal Fury 2 is a good choice for big KoF fans to see how the game started, or for fighting game junkies. But the casual gamer is better off with Fatal Fury Special.