Ninja Five-O - Yes the game has some generic looking graphics, but the gameplay is awesome. If you enjoyed Ninja Gaiden & Shinobi of old, you should really love this game. The mechancis with the chain you use to whip around and sword play/timing along with the excellent platforming like you'd expect in a 2D Ninja game make this game very worth getting.
That's the only one I want to touch down on, since everyone else probably listed anything else I'd mention. Ninja Five-O gets no respek.
__________________
~
You should never underestimate the predictability of stupidity.~
Bullettooth Tony (Snatch)