I am a big KOF fan and I don't know what this game was, but it wasn't KOF. There is no story, no ending, no real reason to play. The fighters are slow, the character balance is a joke, and the game is buggy.
If you don't want to ruin your idea of a good fighting game please do not get this game.
Because I am not a totally negative person I will post the good that it has; the online lobby system is great.
It doesn't matter how much you love KOF, listen to the other reviewers and STAY AWAY there is so little to do and absolutely no reason to do it. The achievements will be a stain on your Gamerscore for this is the definition of a phoned in port. No unlockables that I could find, missing fighters GALORE, a single player experience that is absolutely BORING with atrocious cut scenes and questionable controls with lots of cheap leg finishes. All this game has done has made me run screaming back to my DC version of Marvel vs. Capcom 2 the greatest of 2D fighters, the old NEO GEO KOFs are even vastly superior. YOU'VE BEEN WARNED..