Amazingly flexible and highly addictive.
The graphics are awesome and ,on the right tv, it will feel like you are living the experience.
The flexibility of the game is reason enough to buy the game. First off, forge. Basically it is this game mode that lets you edit the maps. Adding vehicles, turrets and a lot more. Also there is theater. Automatically the game will save up to your last 20 games. In theater mode, you can relive the experience over and over.
At the last of the list, there is plot. If you have kept up with the halo series or even if you are new to them, you will find the plot extremely interesting and will get your adrenaline up so you might just have to go on xbox live and kick some ass.