On the negative side, the lack of variety in level design and enemy placement is simply inexcusable. The repetitive level design reminded me of those tunnel missions in VietCong. What kind of madman game designer would want the player to undergo such drudgery? I haven't seen such overt reuse of content since... I dunno Wolf3D. Sometimes you can bypass entire rooms of Covenant by simply hiding from them, as if the devs knew that you no could longer be bothered to fight. Surprisingly this notion came to me earlier in the game before the library mission (The Libary became quite fun once I figured out how The Flood was triggered.)
On the positives, I and others have commented once on how the combat in Halo "just clicks". The somehow it provides an action experience that goes beyond the sum of it's parts. Well after playing through more than half of it I now feel qualified to clarify such a statement.
It's certainly not primarily due to the more tangible aspects of graphics, physics, and sounds.
Some weapons such as the autorifle and the explosives do deliver a bevy of effects and enemy reactions, and feel powerful to boot with associated recoil. But others such as the shotgun and the plasma rifle fail to project much in the way of destructive momentum on the enemy. Besides, we've all seen these before.
The ringworld of Halo is inspiring and impressive, but ultimately looks dated with a relatively sparse number of props and vegetation. Internally it redefines the word "generic", with novelty bump mapping effects.
The sounds have since been eclipsed in terms of quality and content. Technically however I believe Halo has the best positional 3D I've ever heard. Even with my horribly mismatched 4 speaker system I can accurately localize sounds coming from the sides. EAX support is subtle and more ambient in it's approach. Clearly the devs didn't want it to distort the sounds too much. The doppler effects really shine with needles or plasma projectiles.
I believe a good deal of the great action involves the enemy AI. while not truly intelligent it does convey a good impression that it is. While the types of Covenant opponents are few compared to most action games, their evasive movements and excellent use of cover make almost every battle truly unpredictable and keep you on your toes at all times. To survive in Halo you really to be able to think and react quickly to the given situation.
So far I think it's deserving of it's current Gameranking rating.
"Nothing livens up a robotic hymn of doom more than an amazing pair of jugs." - Brak