N+ expands upon the classic for the PC, and proceeds to make it better in every possible way.
Graphics: Yes this used to be a flash game on the PC, so the demands aren't what we call...difficult. But the way this game looks is unique in itself, and having it all in HD, it's just fun to look at.
Sound: While you're playing you get this beat...it's a very addicting beat and it just adds to the gameplay.
Gameplay: This is where it shines. Anybody who played the PC version knows that while the controls weren't hard, they took a little getting used to because of the shift key. Well on the 360, there's the obvious, move with the left thumb stick. But there are 3 different jump buttons, A, LT, and RT. Then the X button is the suicide button (which opens up a few unintended game types). The ninja feel to this is just fantastic, you can wall jump to your hearts content and dodge missiles. Fun times lay ahead. Then there's multiplayer, oh man multiplayer. You can co-op through the entire single player campaign, or do the specifically designed co-op levels. There's races and survival modes as well. Then there's a level creator, so you can make an impossibly hard level (which we did...and now I hate my roommate).
Overall: Overall this game is great, it has an addicting aspect, great look, fun sound, amazing features. If you own a 360, get this. Don't listen to the people who say 800MP is too much for a 13MB download. You get your money's worth.