Utter Ownage! That's all there is to it!
You play as Noble 6, a Spartan-III and a member of the Noble squad of Spartans. Each member of the team has his or her own personality, which are both believable and enjoyable, and you become emotionally attached to them as you shoot and melee your way through the wastelands which used to be ONI's headquarters, and several other greatly designed levels and areas. My personal favourite feature of the game, though, is the fact that you now have a voice, and therefore you can take part in conversations with your squad during the cutscenes, which makes the game much more realistic.
Reach not only offers you great campaign, but also great multiplayer. Firefight makes a reappearance, much to the delight of myself, and new online game modes, such as Invasion and Arena, have been introduced. Combine this with the new weaponry, such as the new DMR, the needler rifle, and the new vehicles such as the Covenant Renevant, a smaller version of the Wraith, and the UNSC's Spectre, a spacecraft which you are able to pilot in one of the missions.
Overall, if you're a true Halo fan, you won't want to miss this. The game is so much more than the previous Halo's, as I said before, and it's one of the best games I've played this year, if not the best!