hl2.jpg[In his latest column for GameSetWatch, UK writer and journalist Fraser McMillan discusses Valve's seminal first-person action title Half-Life 2, examining and revisiting the smart design decisions behind the classic game.]

I've just finished Half-Life 2 for the first time. It has taken me three attempts - once on Xbox 360 and twice on PC - to see Valve's defining game to its conclusion. That this relatively minor feat took so long is entirely my fault, ironically a product of the impatient wish to blast through as quickly as possible.

Two and a half years after I initially booted it up, the end credits rolled. The final, completed playthrough attempt lasted less than a week, and I'm glad I bit the bullet and experienced it this way.

Not that it was anything like a chore; by taking things at my own, or, more accurately, Valve's pace, I had time to absorb the world and explore its nooks and crannies, my eyeline expertly guided by the seemingly omnipotent hand of City 17's creators.

I finally understand why everyone has waxed lyrical about Gordon Freeman's second adventure for the last half-decade or more. Conducive to this is the fact that my tastes have matured, and my thoughts on games delved into deeper, more analytical territory. Articulating why I liked X and disliked Y is no longer particularly hard in most cases.

When I can't explain these, it's usually because I was baffled by just how terrible each element of the design was. On a handful of occasions, though, it's a sign that what I played was so confoundingly fantastic that my critical brain didn't even attempt to kick in. This is the position I'm in now. Deconstructing Half-Life 2 feels wrong in a way, like teasing a dog with some food only to scoff it yourself. It shouldn't really be done because it's against the nature of the beast and could cheapen the experiences of all involved. It's not even entertaining; just perversely, cruelly compelling.

Half-Life 2 is designed so as to not appear designed. That's ostensibly odd, but makes a surprising amount of sense. A lot of effort has been poured in to create the impression of effortlessness. Most of what we do, see or hear in Half-Life 2 feels distinctly of our own volition. If not in the act itself, the mere observation of incidental detail off the critical path is a component of the illusion of presence and agency, even though each individual's journey will, in the end, be effectively identical to other players'.

This facet of its design makes itself known from the instant the G-Man's face fades out to reveal an unexceptional train car. As well as evoking the timeless introduction to its predecessor, this scene serves to create the illusion of reality; of an ambient world that exists beyond just our interfacing with it.

Airborne robots which we'll later come to despise fly by the carriage, inspiring curiosity. A fairly normal looking landscape passes increasingly slowly as the vehicle comes to a halt. Our two co-passengers occupy themselves, one waiting eagerly for the doors to open as the other sits opposite, dejectedly staring into nothingness. We can talk to the latter or leave him be. As we're let off, the former sighs; "Well, end of the line."

With this sequence, Valve instantly and very tangibly contend that though this remains a Half-Life game, it's one of an evolved character. They turned the first-person-shooter on its head with that first title, Citizen Kane-ing the genre to an extreme degree, but the setting allowed the team to concentrate on a specific goal without concerning themselves much with the outside world.

Forced to emerge from the secluded comfort zone of Black Mesa, the sequel establishes itself as both successor and pioneer from the off, and continues in this mould for much of its duration. It should be noted at this point that it's not perfect but - Freeman's basking in the adulation of every NPC notwithstanding - Half-Life 2's universe is absolutely convincing.

Not through the kind of emergent systems that make Far Cry 2's war-torn state so wonderfully plausible, but in an entirely different and equally valid manner, one that single-handedly authored a rigorous and, ultimately, highly successful template for linear video games that is still being ignored to this day.

It's all in creating an illusion of substance and openness and propelling the player through it at whatever pace is required. A lot of elements of Half-Life 2 feel dynamic in nature despite being at least somewhat intended or even heavily scripted.

The odd set-piece is obnoxiously predictable, but in a franchise that lives and breathes on these cues it's astounding how sparse these are. Allow yourself to be engulfed in the sly deception and these fade into such insignificance it's laughable. Many modern releases remain patronisingly transparent without anything close to such a sustained barrage of both subtle and overwhelming instances.

It's equally incredible when you realise just how paper thin the mirage is. Hang around too long in one spot or put on the blinkers and dash through and it's all too easy to break, but even when compelled to do so it's tough not to be rapidly, subconsciously re-immersed. We're the hapless cobras rising from the basket as Valve expertly play their tune, transitioning from staccato to legato when appropriate.

The reminders that this is a fully realised world continuously flow towards us, and by alternately sticking to convention and craftily subverting our expectations of what video games are, Half-Life 2 capitalises on our gullibility to this effect. How clever I thought I was by navigating over to the beach hut using painstakingly arranged miscellany and my trusty old gravity gun. Empty, besides some assorted junk and a small item crate. The ammunition it contained was already maxed out in my inventory.

At first I was scandalized; how dare you, Valve, how dare you so gratuitously undermine my efforts? Then I realized that my impression of this place as a cohesive, unified land that simply exists had been augmented. My irritation morphed into unabated admiration. Why does there have to be an explicit reward for venturing into a hidden or ostensibly unreachable spot? My prize was much more interesting.

Merely paying attention also pays dividends both in terms of the strength of the universe and the narrative. Peering through the view-box in the door you'll see something that often leads to far more questions than answers, but which also fleshes out the core experience. Keeping your eyes peeled means you can witness things that have the capacity to alter your perception of the City and its inhabitants or prepare you for a challenge ahead.

It's unlikely that many players have seen all of these, but both static and active environmental incidentals can frighten, inform, bait or warn. Some allow us to begin filling in the gaps ourselves in imagined ways. We begin to construct an image of who lived in this cell by its contents, what prompted that piece of graffiti or what unspeakable things must have befallen that rotting corpse in the viaduct. It happens infrequently enough to make the player feel special, as if they're the only one to have observed such details. Again, these can prompt the same reaction as a totally unscripted emergent event, but within a much more solid framing than any games of that particular propensity are likely to achieve any time soon.

I've noticed that actual examples of the virtues I've cited are somewhat lacking from this article. Perhaps, though, this stems from the broader effect of believability that Half-Life 2 so decisively realises. It already presents the most attractive science fiction setting yet seen in our medium, but the manner in which it shapes our experiences in such gentle and minor ways is its crowning achievement.

My failure to cherry pick the most impressive of these idiosyncrasies is indicative only of its intransigent formula. Memories of my time with the game are not necessarily of these individual pieces, but of the great chunks of the puzzle they gelled into. Firm authorial control in games, Valve have proven, can also relax when properly timed. The most important lesson we can extrapolate from Half-Life 2 is that if you're going to force us down a linear path, you should do your utmost to make it feel as far away from this reality as possible. Maybe it's obvious advice, but it's one that far too few have taken onboard over the years.