Half-Life 2 remains one of the best single player experiences available, even 3 years after its release.
To set the scene I will begin at the beginning. The original Half-Life, another classic game that those who have no picked it up should burn for. Half-Life put you in the shoes of Dr Gordon Freeman, a theoretical physisist working in the Black Mesa complex, a giant underground scientific facility built somewhere beneath the Nevada desert. Not to spoil things for those who have yet to play it, but obviously something goes horribly wrong, and you have to put things right. At the end of the game you are confronted by a suited man (hereby refered to as the G-Man), who gives you the choice to work for him, or the choice to die! Half-Life 2 (obviously) assumes you chose the former, and begins with Gordon waking from some purgatory-esque statis by the G-Man. His words are vague and cryptic, and he leaves you on a train headed straight for City 17. At this point, you have absolutely NO idea what is going on. What has become of civilization? Who are the mysterious 'Combine' police who oppress the city? Who is the face that fills the huge screen around the city and re-assures the citizens that co-oporation will lead humanity to the next step? Many of these questions are answered, but many are left for later parts of the series. Because the perspective never leaves that of Gordons, you only piece together pieces of the puzzle by hearing, seeing and experiencing the events first hand.
You run into Barney (a security guard from Black Mesa, who works for the Combine in order to spy for the resistance), and it quickly becomes apparent that you are not welcome in the city. You are chased by the Combine through apartment blocks and into the lovely hands of Alyx Vance, daughter to one of the scientists you worked with at Black Mesa. She in turn leads you to the secret lab of Doctor Kleiner, another scientist you worked with at Black Mesa. It is from here that things again go wrong, and where the game begins its intense and memorable road to its cliff hanger conclusion.
On your journeys you will head through canals (in part on a hovercraft), through a zombie infested ghost town, along a coastal highway (in a buggy), to a Combine prison and eventually back to City 17, in order to scale the Combine Citadel and put a stop to Dr Breen. All of the locales are absolutely stunning and vary wildly. As a game Half Life 2 is a very complete experience. Though the majority of the game is mearly getting from point A to point B intact, the scenarios and locales are handled so well that you never feel like you are playing through a similar part again. Though your main enemy is the Combine, you will also come up against many other enemy types, old and new. Those of you familiar with Half-Life will no doubt welcome barnacles, the iconic headcrabs and their subsequent zombie counterparts. Added to their repetoire are new fast zombies that sport super agile headcrabs, and the slower hulks. These lumbering zombies have poison head crabs literally sucking the life out of them as they stumble around. When they see you they won't hesitate to chuck one right at you, and if bitten by one of them your health is temporarily lowered to 1, so definitely kill these first in a room full of zombies!
Along with the zombies there are many new enemies you will face. The Antlions are a race of arachnid aliens asthetically similar to the bugs from Starship Troopers, and the larger guards are truely a terror to fight. Manhacks are flying mechanical saws that are thrown from a Combines waist. Striders are giant tripod like creatures, part flesh part machine, that can rain fire from turrets, or power up an intense beam of energy that can take down buildings. Hunter helicopters are pretty much just that, but with the added ability of dropping timed mines that explode within about 3 seconds, unless hit first. Finally of note are the Dropships and Gunships. Though their function is pretty obvious from their namesakes, their design is not. What can only be described as part marine life, part mammal, part machine. That flies. And Shoots!!
A wide variety of weapons is provided with which to dispatch the large number of enemies against you. Along with the iconic crowbar and the obvious pistols, machine guns and shotguns you also pick up grenades, crossbows and rocket launchers. The best new addition though, is the Zero Point Energy Manipulator, or Gravity Gun for short. With this weapon you can pick up, put down, push and throw the majority of the objects in the game. Not only does this add a level of depth to the combat (just wait until you pull a radiator off the wall and chuck it at a combine soldier, or better yet, pick up a saw and slice a zombie in half with it!), but it also means that many puzzles can be set up with Gravity in mind. The physics engine used in the game does a great job of putting all of these elements together cohesively and believeably.
The AI for the most parts is decent. It's no where near as good as HL1's, but still does a decent job. Soldiers flank you and use grenades intelligently, but all too often they stand out in the open and just wait to be mowed down. A pity, but not much of a hinderence on my gameplay experience.
The gunplay is intense and only lets up so you can enjoy one of the emotional scenes courtesy of the uncanily believable models and voiceovers. Characters often look scared, concerned, happy or angry. They hug, hold hands, wink at each other, clap and act out many other belivable mannerisms. It really has to be seen to be believed. The character models are all very detailed and polished, and the lip synching is spot on, adding to the immersiveness.
Graphics on the whole are excellent. The source engine truely is a sight to behold. In my opinion it is the only engine that has created textures that in any way resemble real life. Obviously since it's release games like Crysis have emerged, but 3 years ago (or there about) this was the epitome of graphics. The fact it still stands up to this day is testament to that. Take a look at the water when 'Reflect All' is checked in the graphics options, and it's hard not to just stop and stare...
Since the release of Episode One, HDR and bloom effects have been added, which only help to improve an already outstanding engine. But even without these, the game looks AAA.
The soundwork in the game is pretty ****ing amazing as well! My only quibble with the effects is that a few of the guns sound incredibly tame (especially the pistol, which sounds like some one flicking a rock off a desk), but the environmental sounds are all spot on. The artistic direction that went into the Combines sounds is simply astounding. You're not likley to forget the cries a Strider makes as it comes crashing down, followed by the intensely bassy powering down. The music is also a mix of solemn synths mixed with faster dancier bits when the action is at its wildest.
The voicework deserves a paragraph of it's own. All of the characters recite very credible pieces of dialogue very believably. Without the amazing voice acting it would be harder not to feel betrayed, sad, worried, happy or relieved for/by them. The script is very good. Not one character stands out as better than the others, and as an ensemble you have all the elements there perfectly.
In closing, if this (and all the other) review(s) haven't swayed your opinion, then nothing likely will. But you owe it to yourself to give it a go. One of, if not, my favourite game(s) of all time. Buy it.