There is a certain thrill using the enemies own weapons against them dont you think? Not only this, but you can fire gas canisters at Zombies who set alight and scream in pain, and if you wish to administer a rather quicker death then the various circular saw blades make short work of slicing unfortunate opponents in two. In one later and rather memorable level the Gravity gun takes on a whole new meaning and power, causing much hilarity as I ploughed through scores of troops sending them in all directions!

The rest of the weapons include all the usual suspects, Pistol, SMG, Shotgun, an (underused) crossbow as well as a couple of others I shall leave you to find for yourselves. All the weapons feel and sound weighty, each packing their individual punch. They also have rather different specialties meaning you have to swap between weapons depending on the situation at hand This is rather nice as you find yourself using the full range of arsenal at your disposal rather than sticking with one "usual suspect" for most of the game. As you navigate your way through City 17 and its surrounding areas, you will find yourself traversing a variety of different environments, each with its own effect on game play.

The 2 levels that use vehicles are like a rollercoaster ride, both the airboat and buggy handle exceptionally well, and the turbo on the buggy is fantastic. Like wise the mounted gun on the airboat brings a new level of destruction to play. If anything though, I found the airboat level slightly on the long side, although it does inject another level of adrenaline into the game. Again, the physics are fantastic in the way vehicles respond to the environment. Ravenholm provides a darker side to City 17, and an excuse for the mindless slaughter of zombies and head crabs fully utilising the newly acquired gravity gun and a verity of cleverly thought out traps. When you re-enter City 17 later in the game, you find yourself fighting along side resistance members, against a formidable force of soldiers, accompanied by the immense Striders. The level of intensity and destruction brought to these later levels rivals that in Call of Duty, and is simply breath taking. It is also here, where you really experience the level of AI present in the game. In general, AI is very good. Squad members do what is asked of them, although a minor criticism is that beyond telling them where to go, you have little control over their movements. While they can hold their own in a fire fight, they do seem to die a little too easily at times. This is not too much of a concern as you tend to attract a following equally as easily as you fight yourself through the city. Enemy AI is challenging, and I found squads of combine forces to be far more rewarding to fight than the zombies which obviously have a more rudimentary "search and destroy" mind set. Soldiers flank and work well together. Valve has given its AI far more polish than say Far Crys AI, which was arguably the previous best.

If you run your vehicle through wooden supports holding up a structure containing many soldiers, you will break those supports and those soldiers will come crashing down. It is a very realistic game, and due to the realistic feel it gives the game, it makes the game only that much more fun.
However is there a point to this new physics engine? Does it actually effect actual gameplay/combat? Yes it does.

Taking advantage of the physics engine allows many alternatives to killing an enemy rather than just shooting it between the eyes.

It also gives the game designers the ability to mix up the challenges with not just shoot-outs, but puzzles that require thinking and the interaction of objects around you to solve.

The only downside to this physics engine is that there were a lot of unnecessary and rather stupid puzzles put in to place just to show off something that the engine could do that wasn't even all that interesting. Other than that the puzzles presents by this new physics engine were usually fun and interesting, although a little confusing at times!

All in all, the physics engine is an extremely huge improvement of physics in the FPS arena, and is one of Half-Life 2's best points.

Sliced! The grav-gun in fantastic fun.

Striders Hard to kill!