Once upon a time, first-person shooter games had about as much plot and character development as a porn flick. Your digital hero just ran around and pumped hot lead into demons or aliens or Nazis, much like the porn hero pumps ... well, let's leave that analogy there, shall we?

Then, in 1999, along came a shooter called Half-Life that had an interesting story, memorable characters and cool movie-like setpiece encounters. Suddenly the games biz was awash in buzzwords like cinematic, immersive and artistic. Said with a straight face, no less.

As the sequel to one of the best-known and best-selling PC games of all time, Half-Life 2 has a lot to live up to. And although it doesn't usher in a whole new way of looking at games the way the original did, it's easily one of the most technically impressive and genuinely fun PC titles of the year.

A lot has happened since the original Half-Life, including humanity pulling a France and surrendering planet Earth to the alien invaders from Xen. As bespectacled research-scientist-turned-action-hero Gordon Freeman, it's up to you to lead the downtrodden human resistance in a revolt against the aliens and their powermongering human allies.

Sounds gripping, but that might be giving it a little too much credit. The thin plot of Half-Life 2 is one of the game's only real weak points, and is mainly used as an excuse to string together Freeman's gun-totin' escapades from the alien-controlled City 17 to a deserted prison used as the conquerors' HQ, with many a stop in between.

But trust me, brothers, sisters and other family members, you're not going to care much. Half-Life 2 is the most amazing-looking PC game to date, full stop. You can argue Doom 3 does lighting and shadow better, but Half-Life 2 beats Doom 3 with a stick when it comes to creating a game world that's immersive, interactive and (I hope this doesn't sound too poofy) genuinely beautiful at times.

(One disclaimer: I played the game on a rig built around an ATI Radeon X800 Pro, one of the best video cards available, and Half-Life 2's graphics hardware of choice. On lesser machines, your mileage may vary.)

Physics - the bane of many a high-school student - plays a key role in Half-Life 2's fun factor. Most objects in the game world look and act exactly how you'd expect them to, whether it's the corpse of a Combine soldier bobbing eerily in a pool of water or the dune buggy you'll pilot in a wild cross-country trek to rescue one of your fellow freedom fighters.

One example of the game's physics engine in action: In the alien and zombie-infested town of Ravenholm, I triggered a pre-fab booby trap and lured a couple of critters into its whirling blade of death. The blade broke off when it sliced the first zombie neatly in two, spun through the air and hit a steel barrel full of fuel, which exploded and set the second zombie on fire. The creature then screamed and staggered around before collapsing in a smouldering heap. Oh. YES.

And that was no scripted event, either. The game world is yours to experiment with, especially once Freeman acquires the gravity gun, a device that lets you pick up virtually any non-organic object and fling it around with abandon.

You can use it to blast aside wrecked cars and other debris blocking your path, fling circular saw blades into approaching zombies or just play a friendly game of catch with a lumbering robot nicknamed Dog. After the trap mishap, I picked up the broken blade with the gravity gun and had a merry ol' time whipping it into the advancing undead horde.

Everything in Half-Life 2 is polished to a shine, from the intricately constructed environments to the cast of supporting characters who act, react and emote with a level of realism never before seen in a video game.

Which isn't that surprising, given the game's epic five-year development time. While Half-Life 2 is linear almost to a fault - there's only one route through the game's sprawling levels - it's so well done that you rarely feel hemmed in.

The weapons, many of which return from the first game in a slightly tweaked form, are varied and satisfying, and are trickled in at a perfect pace. (Wait'll you get the "bug bait" that lets you control the Starship Troopers-esque xenomorphs called ant lions. Watching them tear a swath through a Combine gun emplacement is disturbingly satisfying.)

One of the few disappointing things about Half-Life 2 is Counter-Strike: Source, the multiplayer component. There's no denying this gussied-up remake of the beloved Half-Life terrorists vs. counter-terrorists mod is one of the best online shooters out there, but it's essentially the same game we've been playing for almost five years now.

I would have loved to have seen a multiplayer variant with sci-fi-themed maps and using the stable of cool Half-Life 2 weapons. Can you imagine a deathmatch with gravity guns, chucking around cinder blocks and washing machines? Just the thought of it makes my inner tail wag.

But no matter. Like recent five-star crown jewels Grand Theft Auto: San Andreas and Halo 2, Half-Life 2 represents the pinnacle of what the video gaming medium can offer. We've come a long way since digital porn, baby.

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BOTTOMLINE

A gaming masterpiece that combines groundbreaking technology, atmosphere and all-out action. It's the closest you'll get to starring in your own sci-fi flick.