An arcade feel, but with cool graphics, great ninja tactics, and about a thousand weapon combos to keep you coming back.
So far my favourite weapons are the hand and foot claws ("Falcon's Talons") and the dual katanas ("Dragon's Claw and Tiger's Fang"). The massive "Eclipse Scythe" is also very useful for larger oponents and bosses, and the "Vigoorian Flail" seems fun and pretty effective but I haven't used it much.
I think that although the developers did a great job of making the game run smoothly, the texture quality and polygon count of the environments is a little lacking, and there isn't much in the way of environmental effects, other than the odd bit of fog here or there. Some of the lighting is very good, and the character models are very nicely detailed, which helps make up for some of the definciancies, but I think the game would be even better if they could have included higher-res textures.
The best part, of course, is the fighting. You'll mame, dismember, mutilate and vanquish thousands of enemies in graphic ninja form, blood spurting everywhere and in pools, body parts scattered all over the place. The action is lightning fast, vicious and totally engaging. Awesome!
The bottom line is that it's a totally fun game to play, with lots of replay value considering all of the different weapons and techniques you can attempt to master. Get it, and try to beat my karma scores online