People have been using Master Chief to battle the Covenant for years and it seemed at the end of Halo 3 that the war was over. The Covenant was defeated and Master Chief and his A.I. Cortana were thought to be lost or dead.
Of course, in the videogame world that's never true, so Master Chief and is A.I are back to face both new and old foes. I could go into the plot of the game about The Flood Composer, etc., but I'll leave that to you. Halo has always been heavy on the emotional impact and storyline and this game is no different.
I can guarantee you, the ending will move you to tears no matter how much of a manly man you think you are. The guts of this game is the fighting. Master Chief has his traditional array of weapons at his disposal as well as a host of new ones.
Anyone familiar with Halo: Reach will be familiar with the mechanics of this game. Lets face it, they are all basically the same types of gameplay just different plots. Let me just say that I loved this game. I never got into the Halo games until I played Halo Reach and this far better than that game.
It contains not only the primary storyline mission, but also a host of co-op options as well. The game has a huge replay value because of the co-op play and I am sure there's going to be tons of downloadable content.