Nor does half-life 2 suffer from tedious repetition. Just when you are tiring of a certain section or a current environment the game throws something new and fresh at you. Probably the most enjoyable spritzer is the prodigious use of vehicles in the game. There are two major portions of the game which see Gordon riding a vehicle into battle. The first is an airboat which Gordon uses to escape from City 17. This long and meandering section interposes steady exploration and puzzle solving with flat-out moments of hectic action. So while one moment will see you checking out an abandoned warehouse the next will see you leaping over debris and across channels while under relentless fire from a pursuing gunship. A few chapters after the conclusion of your airboat ride Gordon is despatched along a costal roadway in a jumped-up dune buggy. The buggy sections are another delight, again mixing up steady driving with ludicrously intense combat sections. Taken all together these vehicle based sections comprise around just under a third of the total game. Yet they don't outstay their welcome. Like the rest of the game there's enough variation in the obstacles and situations that present themselves to keep the entertainment and interest ratings high. And the pacing is spot on. It's so good as to be imperceptible, but you will be aware of the tingling feeling of your brain's satisfaction centre being liberally pleasured.

Now to the meat of the game. The combat. The AI of the first game was a revelation; the marines were at the time a giant leap forward in terms of presenting gamers with a challenging and realistically behaved foe. High hopes were thus understandably had for the combat dynamics of its sequel. Most unfortunately, the AI in is a let down. While a game must maintain that the gamer is fighting a real foe while leaving the virtual enemies susceptible to the players gaming prowess, gamers want to play against enemies that behave with some sort of intelligence. And the enemies in Half-Life 2, while not idiots, could certainly do with a tactical training course. Maybe it's a fault of the less claustrophobic level design, but this time round I rarely felt myself duped into believing I was shooting at anything more then some basically programmed computer game baddies. They will make use of cover and they will occasionally press forward together but all too often the Combine soldiers would just stand there trading bullets, an exchange they invariably lost. Now, there are a number of set-pieces where the location and number of foes conspire to create a hectic and realistic fire-fight but the majority of soldiers that you will gun down as you progress through the game are little more then animated targets.

Headcrab behaviour is identical to the first game and the shambling zombies are also only dangerous when massed against you in a tight spot. There are new headcrabs which are rather disturbing, but this is mostly down to their greatly increased toughness. The Ant Lions, the one truly new alien foe in the game, will sprout wings and come at you from both the sky and the ground but again they only present a problem when you are backed into a corner or running low on ammo. Which is something that very rarely happens. In fact, I can only recall one time when my reserves were down to an underwear staining level. Still, the massive striders that show up near the end of the game will take your breath away, especially when there is a pack of them hunting your squad down. The gunships that make an occasional appearance are also something to respect, although once you get the hang of using the laser sight on the rocket launcher to guide the agents of their destruction in they become rather simple to defeat. Especially as you are guaranteed a crate of unlimited rockets each and every time you are meant to destroy these large vehicles.

So the AI seems to be a step backwards in many respects. The soldiers will still toss grenades at you and with their illuminated red-tips that draw a lazy arc in the air as they spiral towards your position they are always an engaging addition to any firefight. You have to be careful not to toss in too many grenades at once, as the explosion of the first can easily send the second flying back in your direction. I still loved shooting everything in sight, and the weapons go along way towards making up for the deficiencies in the AI. Many old favourites are back, such as the Magnum, rocket launcher and shotgun. They are joined by new weapons such as the Combine pulse-rifle, an ultramodern assault rifle which makes up for its poor accuracy at range by packing a strong punch. The SMG replaces the MP5 while filling essentially the same role, and the Bugbait is an ingenious weapon which allows you to call tame Ant Lions to do your dirty work for you. Unfortunately this last weapon is only available during a few strictly defined sections.