Halo CE is a goddamn weird shooter. I did not play Marathon the first time I played Halo but now I can see that there's quite a lot of Marathon DNA in Halo: and I'm not referring just to the graphical throwbacks, but to gameplay elements that are clearly an evolution of concepts (and problems) that Bungie already had with Maraton. Hell, there's even a little ONI in Halo (the layered shielding and the dreadful plain grey levels!).
It's still a weirdass shooter. I guess one needs to firmly set it in its age and role, for a 2001 console FPS this thing must have been mindblowing, but from a general shooter perspective Halo has to contend with stuff like Serious Sam and RTCW, and even relatively older games (classics like Quake) easily beat it on several levels. But as a console shooter? This must have been insane.
Graphically, it's weird. The engine is functional and when it's at his best (I'm referring to the original, the remade version is completely generic) gives you nice vistas for 2001, particularly The Silent Cartographer and Two Betrayals, but at the same time you're endlessly dumped in nondescript grey areas that look like some cheap Half Life mod. The models are nice but I find them completely devoid of.... how to say, soul? The Covenant look like The Most Generic Sci-Fi monsters, and the Flood are your usual zombies. Marines and their tech are painfully generic. There's nothing of the craziness of Serious Sam's bestiary or the wonderful beauty of RTCW Idtech3 SS troopers. Much like Marathon, it feels generic and bland.
The sound design is competent. Soundtrack is functional if bland. Enemy sounds are well done: I consider a sign of great design when you can easily use sound to identify foes, attack patterns, who's attacking you and from where and with what. Halo makes everything very clear to recognize and understand, and the grunts and screams and chatter of your foes add both ambience and give information.
Gameplay needs some extra words. Enemy design is probably the best single piece of design that Halo offers, and that's only for the Covenant: the other two foes are essentially there to waste space (the Sentinels are generic flying enemies with bad aim and the Flood are generic armed zombies with the frankly puzzling Infector enemy). The Covenant are great as enemies, and I'll almost admit that they made a better bestiary compared to any 2001-era shooter. Their variety is great and gives you an excellent array of foes that needs to be quickly identified and destroyed, every one of them with some small little somethings instead of "shoot at them until they die". Grunts and their need for leadership and morale breaks: Jackals and their pistol overcharge and shields, the numerous variants of Elites, with shields and camo fields an' swords an' grenades, miniboss Hunters (if you fight them as you're supposed to do of course). And they're fast and reactive, jumping and seeking cover. A heritage from Marathon is clear in the "tier" of enemies indicated by colour, giving them extra abilites and equipment and escalating the danger yet giving the player a chance to learn and adapt. Some serious work went into the Covenant....
.... and then everything gets dumped into the gutter with the Flood, that are generic as hell, unthinking, and flat out boring. The Infector variant is a completely puzzling enemy for me, because I can somewhat try to understand why it exist (extra pressure for the player? wasting ammo?) but when the standard procedure for killing it becomes ignoring it until the fight is over and let it suicide against you - or ignore it wholesale - something went wrong.
Furthermore, the Flood murder the careful and fun Covenant fights. From Two Betrayals on, but particularly in The Maw, you can simply ignore the game and soldier on (and this on Heroic!) while the Flood and the Covenant play the game for you. You can walk merrily for a good % of the level without bothering to fire a shot! Entire fights where you enter the room, ignore everyone, follow the green light and exit the room. Masterful design.
This leads to map design. Hell, CE keeps being weird. Some levels are.... you know it's easy to go over all of 'em.
Pillar of Autumn: it's a boring grey corridor devoid of any level design whatsoever.
Halo: I'd say this one is one hell of a change: from a corridor you get open spaces and even objectives you can choose to approach in the order you like, with fortifications and enemy dropships that give you warnings and enemy locations. It's a great level IMHO, Halo at its best.
Truth and Reconciliation: With a beginning that tries to almost a stealthy insertion and some amusing arena fights with AI mates, it quickly devolves into boring corridors with cheap trash spawns and the occasional open space. The Hangars in particular are hard as fuck, I liked that.
The Silent Cartographer: it's such a neat map. Open spaces, free exploration, underground levels.
Assault on the Control Room: mixed bag. Nice vehicle sections, but now it starts. The copy&paste. Entire sections of this level are copy&paste, boring grey areas thrown at the player to pad time. Padding, shameless padding.
343 Guilty Spark: outside of the cinematic jungle and survival horror ambience, you get a shitton of copy&paste padding. Now with Flood!
The Library: You didn't like copy&paste grey rooms? What if we copy&paste entire levels and fill it with Flood?
Two Betrayals: let's recycle entire levels, but this one at least gives you some good fights on open areas and bridges.
Keyes: Ignore the Covenant and the Flood fighting each other, enjoy the wonderful corridors devoid of any design and the recycled content. Aren't you entertained?
The Maw: Ignore the Covenant and the Flood and the Sentinels fighting each other, enjoy the wonderful corridors devoid of any design and the recycled content. Aren't you entertained? Also Warthog run.
Halo throws in the towel early. I've read somewhere that the dev cycle was insanely accelerated, and the game clearly supports this: some enemies and levels were clearly the results of proper work and design while some are nothing but cheaply copy&paste padding. Far more levels than the infamous Library: you can cut everything after 343 and the game would not suffer.
Weapons. For a game that apparently has the most boring arsenal known to man (Standard Human Weapons and three Covenant toys) Halo's weapons are IMHO almost better designed than some better shooters - coff Half Life 2 coff - . The Pistol is one monster of a starter weapon, giving you everything you need, great damage and sniping capability. How many starter weapons are this useful? The Assault rifle conversely is another heritage from Marathon, being essentially a close range spray weapon with pitiful accuracy. I wonder what's exactly its intended use if not as a trash weapon for Flood foes, because the Shotgun is awesome as a standard gun when you get it, almost on Doom tiers of "if you don't know what you're going to fight, get a shotgun". Helped by the fact that the open spaces pretty much disappear after you get it. Sniper rifle and rocket launcher are conventional, but the Covenant weapons show again the care they gave into designing the friggin' aliens with the amusing balance between shield damage/health damage, battery and overheating. Everything with the Covenant seems designed to keep you on your toes, tbh.
Plot: Marathon or Pathway or even Oni it ain't. Aliens bad, zombies, female AI, supahweapon! Hey, at least they kept the funny Bungie level names. I miss Durandal, but I guess the console crowd would have gone insane with that style of writing. Master Chief is the lesser son of Doomguy and the security officer, and for sure he's green, helmeted and bland.
Weird 'un. I wonder what it would have happened if it was release only on PC, and the Xbox wasn't a thing. Probably half-forgotten bar on forums like this one, I'd dare to say...