Slightly more entertaining than eating a bucket of rocks.
Gameplay:
Two good things: The actual ninja fighting is kinda nifty--setting traps, and sneaking up on people. Being able to make your own ninja gear is kinda fun too. But still... it gets old after a very short while.
Overall: Crappy gameplay. You play many missions that are practically the same with some slight variations over and over and over and over again.
(As of this writing, I haven't played the multiplayer, and I probably never will--seeing as single player sucks, and you need multiple cards to play with other people.)
Graphics:
Eh... not that good, but not so horrible that it makes your eyes bleed. Sometimes it's hard to tell if it's a smudge from the pixelated ground texture, or if you're looking at yourself. I dislike that you can't see very far, and have to depend on the mini-map to locate enemies.
Sound and Music:
Annoying and repetitive.
Plot: The Plot is uninteresting and predictable. So that's basically it. Not really that fun of a game. Definitely not worth the money.