Zero Point Energy Field Manipulator

"The Zero Point Energy Field Manipulator is not a toy, Alyx!"

- Judith Mossman

The Zero Point Energy Field Manipulator, more commonly known as the Gravity Gun, is a tractor beam-type weapon that was originally designed for handling hazardous materials, but, as Alyx stated, was primarily used for heavy lifting. At its core is a substance that appears to be a Xen crystal. Introduced to the player by Alyx Vance shortly after arrival at Black Mesa East, the Gravity Gun soon becomes an invaluable tool in Gordon's arsenal and is considered one of his trademark weapons.

Overview


The gun has two basic modes, the first (primary fire button) punts objects. This is useful for clearing out barriers and moving heavy objects. The secondary mode (secondary fire button) picks objects up and holds them in its field. These objects can then either be dropped (by pressing the secondary fire button a second time) or launched (by pressing primary fire). In combat, the Gravity Gun can be very useful depending on the types of physics objects available for use as ammunition. The gun can also be used to pull objects over from a distance, allowing Gordon to access supplies or other objects that would, otherwise, be out of reach. It is also worth noting that while the gun can manipulate many objects, some objects are too heavy or bulky to be picked up. However, some of these objects will still move when punted.

Besides its obvious use as a weapon through its ability to hurl heavy objects at enemies, it is also utilized in many other ways. Clearing heavy obstructions, holding up objects as portable shields against gunfire, returning live grenades to their owners, knocking over turrets, removing and reprogramming Hopper Mines, removing Rollermines from vehicles, dragging objects over from a distance, etc.

The Gravity Gun appears to be quite heavy, as Alyx Vance and other characters that attempt to use the gun have some trouble lifting it.

Finally, while the standard Gravity Gun can't pick up organic material, it can be used to effect against some enemies. Manhacks, City Scanners, and Shield Scanners can all be held in the gun's field and launched. The gun can also punt Headcrabs and Antlions, inflicting minor damage. Doing so also knocks the latter over, exposing their weaker undersides.

The inner workings of the gun is unknown. It is possible it uses a Xen crystal, as the emitter is almost identical to a sample being studied in Eli's lab in Black Mesa East.

Dark Energy Field Manipulator
In Citadel security systems, the Gravity Gun seems to simply absorb the weapon confiscator's energy, while other weapons are destroyed. In doing so it shorts out the weapon confiscator in the process, prompting Overwatch to announce "Warning, counter-resonant singularity device detected. Confiscation Field failure." Once supercharged, the Gravity Gun emits blue light rather than orange, it quakes in Gordon's hands and creates small bolts of energy across its muzzle, and is vastly strengthened. It can hold larger objects, launch them at greater speed, pull with more force and even pick up and launch living creatures (specifically Overwatch Soldiers) to their deaths. Also, holding someone in the Gravity Gun's field appears to electrocute them and destroy their weapons (though this is probably an effect of the Citadel where it's used, as enemies killed by Alyx also have their weapons vaporized), and the body will spark and twitch, once dropped.

The first time the Gravity Gun is supercharged is in Half-Life 2's thirteenth chapter, Our Benefactors, when Gordon's pod deposits him into a Confiscation Field and remains so until the end of the game. During this time, Gordon's HEV Suit also becomes 'supercharged' to the point of harboring 200% energy, and power chargers now garnering the ability to charge Gordon's health as well. At the start of Episode One, it is no longer supercharged, but becomes charged again after Gordon and Alyx re-enter the Citadel to stabilize the core, and Gordon accidentally enters another Confiscation Field. It remains supercharged until Gordon reactivates the core's containment field, at which point the Gravity Gun reverts to its normal state.

After leaving the Citadel, the Gravity Gun never becomes supercharged again. Valve has confirmed that, sadly, the Gravity Gun will never become supercharged again due to the difficulty of incorporating it into the gameplay of the level.

Using console commands or exploits, if the player picks up a Combine APC using the Dark Energy Gravity Gun, the game will either slow the framerate down dramatically, or crash the game. The muscle car should not be picked up due to faults in the physics engine.

Behind the scenes
As heard in sound files featured in the playable Half-Life 2 Beta files, Eli was to explain Gordon at Black Mesa East that the Gravity Gun's "grand daddy" was used to manipulate hazardous materials in the Combine's portal reactors, suggesting the Gravity Gun uses Combine technology.

Trivia

 * The Gravity Gun bears a vague resemblance to the Anti-Mass Spectrometer from Half-Life, as well as the Portal Gun from Portal.
 * In Episode One and Two the supercharged Gravity Gun can be activated in normal use by entering the console command "physcannon_mega_enabled 1".
 * When dying with the supercharged Gravity Gun, it disintegrates.
 * The Gravity Gun is present in Garry's Mod as a starting tool. However, it cannot be supercharged by any means. If the player enters a Confiscation Field, all weapons will be destroyed as normal, except the Gravity Gun which just sits on the ground. To get around this, the player can use several console commands which control the behavior of the weapon such as "physcannon_pullforce". These commands are native to the Source engine; they can increase (or decrease) the power of the weapon to meet the supercharged version, however it still won't affect people. This might be intentional, as the supercharged Gravity Gun's skin is used by the Physgun or Physics Gun, a beta weapon resurrected in Garry's Mod as an integral tool.
 * The film District 9 features an alien weapon similar to the Gravity Gun, built into a powered armor suit. It is able to pick up almost anything, including a pig, and hurl it with incredible force. It appears to have a much stronger field since it is also able to halt bullets and in fact keep them in an area just ahead of the muzzle, somewhat similar to a zero point energy field.

List of appearances

 * Half-Life 2
 * Half-Life 2: Deathmatch
 * Half-Life 2: Raising the Bar
 * Half-Life 2: Lost Coast
 * Half-Life 2: Episode One
 * Source Particle Benchmark
 * Half-Life 2: Episode Two