Not even Halo's most glaring faults can stop it from being one of the best shooters for any platform.
As far as console first-person shooters go, you can't really ask for much more than what Halo provides: back when it was released it included a lengthy, memorable campaign with great action and an intriguing sci-fi storyline. It has local multiplayer of up to four players, and can even support up to 16 local players with system link. It even has an amazing soundtrack with incredibly solid voice acting despite minimal character development. That's pretty significant for a console first-person shooter released in 2001.
So what does Halo provide that I didn't enjoy? Certain aspects of its game design are inherently flawed and incredibly annoying. As the first several levels of Halo unfold you will be treated to an excellent single player campaign with a lot of challenging firefights and some unique and interesting areas to explore. Early on however, you'll notice some of Halo's immediate, lesser flaws. Most noticeably from the get-go is that Halo reuses a lot of architecture and textures. This isn't really as huge of a deal as some may claim but it does start to get grating after a while when you encounter the exact same room again and again with absolutely zero deviation. Thankfully Halo's gameplay is solid enough to carry it through these somewhat sluggish sections without too much disdain.
One of the biggest problems with Halo however, is the warthog. The warthog is a vehicle you can control during certain parts of the game which can be useful for quick transportation. Unfortunately the warthog controls like it's consistently gliding around on a sheet of ice and is nearly impossible to control without unintentionally slamming into objects in the environment and unintentionally flipping it over time and time again, forcing the game to lose all of its momentum when vehicle sections come to a startling halt. Warthog use is mostly optional during these sections but for the most part it's not completely unusable. The warthog is however, solely responsible for one of my most despised moments in the entire game, but more on that later.
After some excursions with the warthog in the early game Halo's campaign begins to find its legs and unfolds nicely with some (mostly) excellent pacing and varied encounters with the game's enemies (despite some copy/paste environments). For the majority of the game you'll face off against the Covenant, a group of sentient aliens hellbent on the destruction of the human race. The covenant comprises numerous alien species so encounters with them are often unique enough to provide a challenge.
The covenant's numbers however are not that large, for the most part you'll face off against horde after horde of grunts, jackals, and elites, with the occasional hunter squad thrown in for good measure. The lowly grunts live up to their name, and will cower in fear often running away if nearby elites have been vanquished, but can still provide a decent threat in greater numbers. Jackals wield large shields and frequently like to fire super-charged plasma bolts that will instantly sap out all of your armour's shields - something that will prove to be greatly annoying which often made them priority targets, even before elites in certain situations. While the gargantuan hunters may be the most feared enemy, elites are not to be taken lightly and will often provide the greatest challenge throughout the entirety of the game. Like Master Chief, elites have recharging shields that protect them from harm, they're also much smarter than the average enemy and employ battle tactics such as sidestepping and evasive maneuvers. Gone are the days of simply tossing a grenade and watching as your foes are easily vanquished. The elites play a huge role in what consistently makes Halo so challenging and fun to play, especially on the harder difficulty settings.
If you think you're only going to face off against the covenant for the entire game, then you'd be mistaken. Roughly two thirds through Halo you will encounter an enemy known as the Flood. The flood add variety to a campaign that has largely been about fighting the same covenant forces over and over again, but they are also single-handedly responsible for one of the most frustrating levels in video game history: the Library. The library is the only level in the entire game where you fight against the flood exclusively, but you also fight against never-ending hordes of them. To make matters worse the flood are equipped with weapons from both the humans and the covenant, and are also sturdy creatures with powerful melee capabilities. This isn't too much of a big deal aside from the fact that Bungie thought it would be a good idea to give some of the flood rocket launchers which can instantly kill you at full health. There's also walking gasbags that explode when nearby, instantly draining all of your shields and unleashing a barrage of tiny headcrab-like creatures.
Thankfully Halo's weaponry excels at taking out all of the creatures you'll encounter in the game, but the VIP award goes to the shotgun, which when finally acquired around the time you're first introduced to the flood will be the first and last thing you go to to save your ass time and time again. The shotgun is hands-down the best weapon in the entire game, at least as far as the campaign is concerned. Aside from your typical assortment of human weapons, there's also an interesting collection of covenant energy-based weapons. The needler is completely useless, similar to the human assault rifle (which is only really useful at the beginning of the game), but the plasma rifle and plasma pistol are both great weapons and when combined with the shotgun make an excellent companion weapon for draining the elites of their pesky shields.
As mentioned earlier, Halo contains numerous different drivable vehicles, the most fun of which being the covenant's ghost and banshee variants. The ghost is a super-fast hovercraft that can fire an endless barrage of plasma and unlike the warthog is actually relatively easy to maneuver. The banshee is essentially a flying ghost but with an added fuel-rod cannon which can shoot heavy blasts of green energy to deal massive damage to enemy units. Unfortunately the human vehicles are much less fun to control for a variety of reasons. The tank is a bit unwieldy but is still incredibly useful during the portion of the game that you're given access to it. The warthog however, aside from controlling terribly also has no defensive capabilities unless you have an AI marine in the back seat manning the turret. They're not very good at this task though, so you'll frequently find yourself hopping out of the warthog to deal with enemies instead of relying on your AI companions to take them out.
The biggest problem with the warthog however, aside from all of the aforementioned issues which are largely negligible compared to this, is that during one section of the game you're required to pilot it through what can essentially be described as an obstacle course (even though that's absolutely not what it is) while simultaneously taking fire from enemies with a timer counting down to your destruction. This might sound exciting and it was probably meant to be, but due to the fact that Bungie decided to make the layout of this level absolutely horrid, when you combine it with the warthog's absolutely asinine control scheme it makes this level a complete nightmare and insanely anti-climatic. There's nothing worse than having a supposedly epic moment completely tarnished because of a vehicle with horrible controls. I've completely lost track of how many times I've inadvertently flipped the warthog over and simultaneously gotten killed because of it.
But when it's all said and done? I still love Halo. I can't help but love it. It's such a great game, despite the fact that there's certain parts of it that make me want to take a sledgehammer to my television. Halo's artistic design is unique, it's gameplay is something you won't find anywhere, and it provides as challenging of an experience as you want. Halo is one of the few games that truly lives up to its difficulty classifications: you can bet your ass that you'll feel pretty damn heroic or legendary when you beat it on the corresponding difficulties, I know I did.
Halo has some blemishes, but it's understandable why so many choose to ignore them when looking at the game as a whole. Some of these blemishes I feel are a huge taint on an otherwise absolutely amazing game, but when it comes down to it all they can do is only slightly bring down what is at this point in time one of the best first-person shooters I've ever played, PC or console.