Still kicking ass 5 years on...
I think the thing that makes the Halo series so special is because its a
sci-fi game. You play as Master Chief, a one man army, a Spartan. Along the way you will be fighting a variety of enemies known as the Covenant. They plan on doing something terrible with the 'Halo' the game is set on, and it's down to Master Chief to stop them.
The lowest (and easiest) enemy in the Covenant ranks is a Grunt. It's a small creature and won't cause any trouble on their own. Although be warned, they can pack a serious punch in a large group. Especially if they have back up from the next types of Covenant. A Jackal is next in the ranks, a bit bigger than a Grunt and they will carry shields with them making it harder to get a target on them. They are still relatively weak but are excellent snipers. The main troop of the Covenant is an Elite. They are as tall as the Master Chief and are a serious foe. The Elite will come in various ranks depending on how many enemies they have killed. Starting with a blue minor Elite, all the way up to the sword-weilding gold Zealot. All armies must have some kind of heavy artillery, and this comes in the form of a Hunter. A Hunter is a hive of smaller beings combined into a huge walking battle tank. They have thick armour and are hard to take down. They also carry a plasma cannon so watch out.
As the Master Chief, you will carry human weapons, but you can also swap them out to carry the Covenant's weapons. You can only carry two at a time, so you have to be careful about your choice's depending on the situation. The Chief's main weapon is the Assault Rifle, and its powerful enough to dispose of any enemy. Other weapons include a Shotgun, Sniper Rifle and a Rocket Launcher. The Covenant's guns will usually fire plasma. Their soldier's will carry weapons such as the Plasma Pistol/Rifle or a Needler.
In the single-player campaign you will play through 10 amazing levels, and a great story to go with it. But the main part of the game that will keep you coming back for more is the awesome multiplayer. Play over a variety of maps set in the Halo world, in game modes such as Slayer/Team Slayer (Deathmatch/Team Deathmatch), Capture the Flag and Assault. The multiplayer is at it's best with either 4 players on one console, or link up with other consoles for LAN fun.
Halo is what the Xbox is all about, great gameplay, great graphics, even now in the transition to another generation of consoles. In my opinion, the Halo series has the best mutliplayer ever and should not be missed.
Please check out my Halo 2 review.