Real Old School!!!
When it first came out, the average review scores were basically 9/10, and that is what piqued my interest to begin with. However, I didn't even buy the game until I saw it for $40 pre-played. In the end EB gets the profit that I regretfully wanted to give to Tecmo for creating such a genius of a game.
The game is great as a stand alone product: The game, and if you collect 50 scarabs, the three original Ninja Gaiden games released on the NES. So far, that's four games. On top of that, you got the first Master Ninja Tournament, which is the original game again, but you get to post your score online. Then there's the Two Hurricane Packs, the first being a harder but well worth upgrade to the game and the second is like a ladder match of complete fights with all the enemies throughout Ninja Gaiden plus Hurricane Pack Vol. 1's game and a few completely new enemies just for Vol. 2.
This makes for a total of 6 games total, with Hurrican Pack Vol.2 being the hardest video game experience you will ever face in your life up to date (I can't speak for the future).
Do yourself a favor and pick up a copy because I'm sure it's cheap and well worth it. Please check this game out, especailly if you have XBox live so you can download the three Master Ninja Tournaments. You will thank me that you did.