Halo redefined the FPS (First Person Shooter: You see through the character's eyes) genre and became the game every other FPS had to measure up to. You can sum up why Halo excels above other FPS games in a single word, variety.
Like food, games quickly get dull if you just keep doing the same thing over and over. So it can pay dividents to mix things up a bit to keep the player interested. The problem with this is that you can end up with a game that doesn't know what it is. The designers try and cram too much into it and it ends up trying to do everything and doing none of it well. When you scrutinise Halo, you find it is stuffed with variety.
There are driving sections and flying sections in there, but they don't seem tacked-on, they form a natural, seamless part fo the gameplay. The weapons provided are varied too, and importantly, sometimes choice is given, and sometimes you don't get a choice of weapon, you have to use what's there. The environments are varied: with lush, open vistas, swamps, cramped corridors, alien ships etc. The enemies are varied: From chimp-like Grunts, through fast, feline Elites up to the imposing Hunters. The gameplay is varied: The provision of a shield allowed a fundimental change in the was the FPS is played. The player is empowered to be brave for so long as the shield lasts, but when low, the player must seek cover. This results in a wonderful variety of emotions as you go from bold attacks to cowering behind cover desperately hoping your shield will recharge before the enemies catch up with you.
The difficulty is varied: Many games adjust difficulty very cheaply by adding more enemies and taking away weapons and health packs. Not so Bungie (and now 343). Yes on higher levels, there are more enemies. But the enemies are stronger and smarter. Your mad charges that cut swathes through them on the lower levels will see quickly you cut down on the higher levels. This forces you to change your strategy and as you do, you discover that you can prevail. The feeling of elation when you take out your first Elite on the Legendary setting is quite a rush.
All that I've written is valid for the original XBox version of the game. The 360 version builds on this by ramping up the graphics dramatically, and making the game look fantastic. 343 have converted the game with great care, attention to detail and with obvious affection. A masterful update.
Oh, and there's multiplayer too, apparently.... ;-)
The "wink" there signifies ironic understatement. The original Halo multiplayer was excellent, and gave a choice of co-operative play or competitive play on a good selection of environments. Halo Anniversary has all that, and adds the benefit of a decade of improvement to the Halo multiplayer experience.
This is a classic game that you really must play if you have any interest in the FPS genre.