Half-Life 2's weapons are, while not as varied as the original game's, fairly diverse. Every weapon has advantages and drawbacks, and knowing which weapon to use in which situation is very important; doing so will make the game that much easier. For most weapons, ammo shouldn't be too much of a concern, as you'll find numerous ammunition drops and crates throughout the game. If you do run out of ammo (which happens very rarely), you can always resort to the Crowbar or Gravity Gun.
Misc.
Crowbar
* Range: Melee
- Max damage: 10 per whack
- Alternate fire: None
- Magazine: N/A
- Reserve capacity: N/A
- Best used against: Obstacles, headcrabs (all types), Zombies
The crowbar is the first "weapon" you find. It comes in quite handy for smashing obstacles, breaking glass, opening crates, or killing headcrabs and normal zombies. It's not much useful for anything else, though. Other than that, you'll only want to use the Crowbar when you're really pressed for ammo (which is extremely rare because ammo is in abundance for most of the game). It is only suggested that you use it for smaller, annoying enemies like headcrabs.
Zero Point Energy Manipulator (Gravity Gun)
- Range: Close to medium
- Max damage: Zero-Instant kill/Instant kill
- Alternate fire: Tractor beam
- Magazine: N/A
- Reserve capacity: N/A
- Best used against: Obstacles, headcrabs (all types), Zombies, Combine soldiers
While technically not a weapon, the Gravity Gun allows you to pick stuff up and blast it away at high speed. This is useful for all kinds of things, ranging from physics puzzles to actual combat. Primary fire fires a beam of energy at objects that knocks them away (this also works on headcrabs and scanners). Alternate fire uses a tractor beam that grasps objects (provided they are light enough), allowing them to be fired with great accuracy using primary fire, or dropped into place by pressing alternate fire again. Towards the end of the game, the Gravity Gun will be "supercharged" so that it can actually pick up organic materials - from Combine soldiers to energy orbs, the Gravity Gun can just about pick up anything at that point. You can distinguish this Gravity Gun by the blue hue it gives off instead of the normal orange one.
Pheropod (Bugbait)
- Range: Medium
- Max damage: None
- Alternate fire Call
- Magazine: N/A
- Reserve capacity: Unlimited
- Best used against: Combine soldiers
Like the Gravity Gun, the Bugbait isn't really a weapon at all. However, Gordon uses it for a much better cause: to summon Antlions. That's right, The Pheropod is actually used to summon Antlions to attack any enemy in the vicinity of the Bugbait's range; in other words, whereever you throw the Bugbait, they'll go there and attack anything in sight. You'll have an infinite supply of Bugbait (and of course, an infinite supply of Antlions). Think of the them as shields and defenders for you, as you'll need them throughout the entire Nova Prospekt chapter. Alternate fire allows you to call them to you to defend yourself and regroup. During most of the game where you can use this item, you won't have any more than four Antlions at one time; however, once in Nova Prospekt, expect the number to go way up.
Handguns
9mm Pistol
- Range: Medium
- Max damage: 5 per round
- Alternate fire: None
- Magazine: 18 rounds
- Reserve capacity: 150 rounds
- Best used against: Metrocops, headcrabs (all types), zombies
The first firearm you will find. While not very powerful, this weapon can has a fast firing rate, allowing a rapid discharge of its 18-round clip. With good aim, this weapon can dispatch even the mighty Combine Elite with relative ease. Ammunition for the 9mm is fairly easy to find, so you may use it often to get rid of obstacles or blow fuel barrels.
.357 Magnum
- Range: Medium to long
- Max damage: 40 per round
- Alternate fire: None
- Cylinder: 6 rounds
- Reserve capacity: 12 rounds
- Best used against: Combine soldiers, Combine elite, fast zombies, poison zombies
A very powerful weapon, this handgun fires the most powerful conventional round in the game. A shot to the head or two shots to the torso with this baby will kill any humanoid enemy. Unfortunately, ammo is scarce, fire rate is slow and reloading is even slower.
Anti-personnel weapons
Submachine Gun (SMG)
- Range: Close to medium
- Max damage: 4 per round, 13 per second
- Alternate fire: Grenade launcher
- Alternate fire damage: 40 per direct hit with grenade
- Magazine: 45 rounds
- Reserve capacity: 225 rounds and 3 grenades
- Best used against: Metrocops, Combine soldiers, antlions
A rapid-fire assault weapon for which ammo is common. It's not at all accurate, and it is even less powerful than the pistol, but it spits rounds out so fast that you'll wonder where that 45 shot clip went. In addition, this gun has a grenade launcher - capable of clearing groups of soldiers in an instant. Because of all these attributes, the Submachine Gun remains a useful gun throughout the entire game.
Overwatch Standard Issue (pulse rifle)
- Range: Medium to long
- Max damage: 8 per round
- Alternate fire: Combine orb
- Alternate fire damage: Instant death
- Magazine: 30 rounds
- Reserve capacity: 60 rounds and 3 orbs
- Best used against: Combine soldiers, Combine elite, antlions
An assault rifle that is mostly used by Combine units, this weapon can handle much better than its other counter-part: the SMG. It's moderately powerful and can be used effectively against any Combine Soldier or Elite as it fires fairly quickly. The alternate fire is somewhat useful but it is very hard to control, as the orb will rapidly bounce around the room and will explode on contact with any organism, including you.
Shotgun
- Range: Close to medium
- Max damage: 48 per shell (8 damage per pellet)
- Alternate fire: Double-barrel blast
- Alternate fire damage: 84-100 per shell (12 damage per pellet)
- Magazine: 6 shells
- Reserve capacity: 30 shells
- Best used against: Zombies (all types), Combine soldiers, Combine elite, antlions
A pump-action shotgun. It looks powerful, sounds powerful and, most importantly, is powerful. This gun is poorer than the pistol at long range, about as good as the SMG at medium range, and is incredibly effective at close range. Aim for the head at close range and for centre mass at medium range. Don't even bother using it at long range. Notably, this gun reloads shell by shell. 6 shells can be loaded into the shotgun at once. Primary fire launches 1 shell, alternate launches 2.
Crossbow
- Range: Long to extreme
- Max damage: 100 per rebar
- Alternate fire: Scope
- Alternate fire damage: N/A
- Stock: 1 rebar
- Reserve capacity: 9 rebars
- Best used against: Combine soldiers, Combine elite
The crossbow is HL2's sniper rifle. It's silent, it has a scope, and it's capable of eliminating almost anything in 1 shot. Despite it's power, this "gun" does have a few drawbacks. First of all, the projectile is not even close to instant, so it is hard to hit moving targets, so unless you have great aim, don't even try shooting one. Next, it can only load 1 bolt at a time, so it takes some time to reload. Lastly, ammo is very scarce. One other, very interesting fact is that if the player aims at the ground at a direct angle towards the enemy, the bolt will bounce right off the surface killing the enemy with great accuracy; this weapon is also known to impale enemies to nearby walls.
Explosive weapons
Fragmentation Grenade
- Range: Medium to long
- Max damage: 125 per grenade
- Alternate fire: Drop
- Alternate fire damage: 125
- Magazine: N/A
- Reserve capacity: 5 grenades
- Best used against: Combine soldiers, Combine elite, stationary turrets
You'll find these explosive grenades fairly early in the game. They're excellent against stationary turrets you'll encounter in later levels, and they're great for taking out large groups of enemies, as well as snuffing them out. You can throw them at fairly long distances, but that distance is rather limited by Gordon's throwing strength. Alternate fire varies depending on your stance. If you are standing up, you will drop a grenade, causing it to land very nearby- usually at your feet. If you are crouching, however, it will roll a grenade instead, which is handy for destroying concealed floor turrets. Remember to stay as far away from grenades as possible, because you can get caught in the blast as well.
If you are good with your gravity gun, you can drop a grenade, then pick it up with your gravity gun and blast it at your enemy.
Rocket-Propelled Grenade Launcher (RPG)
- Range: Long to extreme
- Max damage: 200 per rocket
- Alternate fire: Laser track
- Alternate fire damage: N/A
- Container: 1 rocket
- Reserve capacity: 3 rockets
- Best used against: Gunships, striders
The Rocket-Propelled Grenade Launcher, or RPG for short, is the most powerful weapon in the game. Therefore, it should only be used against the toughest enemies like Gun Ships and Striders. The rockets will automatically follow the targeting laser, making it even more effective against flying targets.