Have you played a fps? If you haven't played Halo, then you truly haven't yet.
With different weapons, modes, and an incredible first player mode, Halo has definatly left it's mark on the gameplaying world. Much more realistic than it's sequel, Halo 2, your aimer is not pulled by enemies, thus making it much more skilled to snipe someone. Rockets and Grenades explode realistically, shotguns are all around realistic, and then you can go into covenant weapons, weapons created for the game, and yet still are extremely realistic. The down side of the entire game, the pistol. The pistol is much too powerful, killing someone in three shots if used correctly.
The maps in this game are amazing, some gigantic, some extremely small, some filled with so many teleporters you don't know where anyone, including yourself, is!
The first player mode is a highlight for this game, ranging up to "Legendary", and playable with a friend in two player mode. The characters are given unique characteristics, such as the marines yelling things in fear, and grunts screaming in sheer terror. Also, the enemy is well done also. It ranges from easy laugh-at-able grunts, to the feared hunter.
This game is sheer genius, and belongs next to every X-box. And besides, who doesn't love Master Chief?