Halo was the definitive game for the x-box and the game that really got the original x-box flying off the shelves years ago. Halo is one of my favorites and it still holds up today as far as gaming standards go. The graphics were simply stunning and still today are better than most PS2 games if not all. The textures and environments are great plus the character models are very good all around. The only problem I have is that a lot of the environments are constantly recycled throughout the game.
The story is another big part of the game and I don't see the point in explaining it because frankly I would be shocked if games didn't know the basics of Halo's story. Anyway Halo's story is really cool and is easily leaps and bounds above most other fps stories and most other games. It's full of great twists and turns and let's just say the turn that the game takes about halfway through is shocking, two words the flood. Master Chief is just about the coolest protagonist you'll play as he just kicks ass. I don't know if we'll ever see other Spartans in the Halo but I doubt any could trump the Chief.
Now the only way that Halo truly could be a great game is if it has killer gameplay and Halo definitely delivers. Generally Halo plays like any fps with a few ajustments. You can only carry two weapons and the two types of grenades. Your weapons loudout consists of the now legendary battle rifle which has a 60 round clip and burns ammo at a very high rate. There the standard pistol with the scope and the pistol turns out to be quite powerful and extremely useful for dispatching some harder enemies. There is a sniper rifle which has it's obvious advantages. You also have the rocket launcher which is great for blowing enemies sky high and dealing with pesky tanks and can't forget the shotgun which is just plain fun and a consistent lifesaver when you get up close and personal with the covenant. So generally the human weapons with good old fashioned lead kick ass. The alien weapons on the other are not nearly as fun. There is basically the plasma pistol which can be charge to fire a mega shot and the plasma rifle which shoots slightly stronger beams of energy at a very fast rate. I don't even want to mention the useless needler. It can be dangerous to you if several grunts happen to be equipped with it. Some of the Covenant carry energy swords which are sweet weapons that you'll quickly begin to fear but sadly you can't use them in the game,luckily you can in Halo2. Anyway the alien weaponry pretty much sucks but unfortunately you will be forced to use it because ammo can be scarce. The one alien weapon that you use that does kick ass would be the all powerful plasma grenade. There are two different types of grenades, the frag grenade and the plasma grenade. Both have uses in different situations. The frag bounces around and generally is good for taking out large groups of enemies while the plasma grenade can latch on to enemies for lethal and humorous effects. And believe me plasma grenades are gonna become your best friends when you got plasma sword wielding elites charging at you. Plus listening to the enemies frantic cries for help in the second before they explode is a very nice touch. But enough about the weapons what really makes Halo fun is the intense firefights that you wage against the Covenant and the flood. The fights are always intense and strategy is a must. The a.i. of your enemies and fellow marines is unprecedented. The covenant will dodge, duck, and take cover and always be using different strategies to take you out. Your fellow marines are the same and in many instances prove to be essential to your survival. So basically in Halo you simply can not run into a pack of enemies guns blazing or you will literally be dead in seconds. To break up the fps sections you'll also have access to human and alien vehicles and many points in the game. In particular the warthog sequences prove to be among the most enjoyable parts of the game. The campaign take about 12-15 hours to complete and the many difficulty modes and supremely fun coop mode adds a great amount of replay value.
Overall Halo delivers an experiance like no other. It mixes a bunch of solid elements togethor and the end result is something great. Sure it isn't perfect and it's only real innovation is having enemies that aren't retarded. But in the end Halo is just plain fun and though it's nearly five years old it is still a great amount of fun. It is essential if you own an x-box or a 360 and though five years later other FPS's have improved upon Halo's formula you'll still find that Halo is a classic.