Ninja Shodown is one of those games where the Multiplayer shines more than the single player experience.  That's not to say the game isn't fun alone; it is, but there's more mayhem to be had in multiplayer, especially Versus Mode.  It's hard to recommend for $15 if you don't plan to play with friends, especially with no online play, but if you have some friends who want to kick up some ninja-style mayhem, you'll want to check it out.