Zero Point Energy Field Manipulator

This article is about the Half-Life 2 weapon. For the cut Half-Life weapon, see Zero Point Generator. For the fan film, see The Gravity Gun (fan film).

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Zero Point Energy Field Manipulator
Production information
Faction	Resistance
Technical specifications
Damage	Varies depending on the object/Normal Instant Kill/Super
Ammo	Infinite
Max ammo	Infinite
Weapon category	1
Ammo type	Objects/Props
Accuracy	Varies
Range	Short to medium
Usage
Maker(s)	Eli Vance
Used by	Gordon Freeman Alyx Vance Wallace Breen (briefly)
Game information
Entity	weapon_physcannon

 

"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 handheld gravity-based device first appearing in Half-Life 2. Said to have originally been designed for handling hazardous materials, Alyx Vance mentions that it was used primarily for heavy lifting at Black Mesa East. After acquiring it, Gordon keeps the device in his arsenal and uses it all the way to the end of Half-Life 2: Episode Two. At its core is some sort of gold-colored substance which is implied to be a Xen crystal by The Final Hours of Half-Life: Alyx. Introduced to Gordon by Alyx shortly after his arrival at Black Mesa East during Half-Life 2's fifth chapter Black Mesa East, the Gravity Gun soon becomes an invaluable tool in Gordon's arsenal and is now considered one of his signature weapons.

Overview

Alyx introducing the Gravity Gun to Gordon at Black Mesa East.

The Gravity Gun has two firing modes. The primary fire releases an energy blast, which punts the held or targeted object with tremendous force. This is useful in-game for removing barriers, or moving objects that cannot be picked up, such as cars. The secondary fire pulls objects towards the gun, and holds them Hitting the secondary fire again drops the held item.. If an object is out of immediate range, but still close, the secondary fire can be held to slowly drag the object towards the player. The secondary fire can only pick up light-to-medium objects, but the primary fire is capable of pushing much larger objects even if the secondary fire cannot affect them. The gun's secondary fire cannot grab most enemies or their corpses, though the primary fire can shove Headcrabs away and flip Antlions over. The Gravity Gun is also handy for moving trapped or overturned vehicles, such as the Scout Car and the Muscle Car.

Using the Gravity Gun's secondary and primary fire modes in conjunction allow it to be used as a powerful weapon. Since it uses physics objects rather than conventional ammunition, there is virtually no limit to how many times it can be fired. This advantage is balanced by the need to "reload" after every shot, by grabbing a new object. Depending on the object fired, the Gravity Gun can be one of the most damaging weapons in the game. Heavier objects like metal barrels and propane tanks can even kill an Overwatch soldier with a single blast, but conversely, objects such as plastic crates, plastic bottles, or wooden pallets will do very little to no damage due to their weaker materials. Explosive barrels, in particular, are highly devastating when used with the Gravity Gun, though this can backfire if the barrel is shot by an enemy while held by the gun. The Gravity Gun is most effectively used as a short to mid-range weapon, since the physics objects it uses for ammunition are affected by normal gravity once they leave the device's hold. The Gravity Gun can also be used to grab larger objects, such as metallic plates or radiators, and holding them up as makeshift shields.

Dog's Zero Point Energy device.

Certain enemies are affected directly by the Gravity Gun; Manhacks, City Scanners, and Shield Scanners can all be held and punted by the gun. Manhacks, in particular, can be held by the gun for use as a makeshift chainsaw. All of these enemies will die if punted directly into a wall. However, if punted over greater distances, they will eventually stabilize their flight. The gun can also be used to grab and recalibrate Hopper Mines or remove Rollermines from vehicles. A Rollermine grabbed in such a manner can be reprogrammed by Alyx to attack hostile targets instead of friendlies, and can also be punted into enemies directly. Combine Sentry Guns can also be manipulated by the gun (disabled by being thrown when being enemies, replaced after being knocked down when being friendly).

Another useful strategy is throwing back a Grenade to its sender. Though this is dangerous, as the grenade can detonate while the player is holding it.

The gun can also be used as an alternative to the Crowbar for smashing supply crates open by picking them up and punting them into the wall, or just punting them on the ground. This becomes mandatory during the first half of Episode One, during which Gordon is without his crowbar, until Barney Calhoun gives him a new one.

The tutorial for using the Gravity Gun takes place in Black Mesa East's outdoor scrapyard, in which Alyx teaches Gordon the basic actions and uses of the device, notably by playing fetch with Dog and his own reprogrammed Rollermine, until they are interrupted by a Combine attack.

Common objects

Some common objects found in the environment that can be picked up by the Gravity Gun. This is a Non-exhaustive list.

Miscellaneous

Includes random items found in the environment. Some items are very light and thus useless for gameplay. Some are heavier and can be used against opponents.

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  Cinderblock, used in a puzzle early in the Canals.

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  Paint can. Does little damage but paints the target white, including walls.

• 

  Watermelon.

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  Sawblade, is capable of cutting Zombies in half.

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  Toilet bowl. Using it to kill an enemy nets the player an achievement.

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  Meat hook.

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  Blue canister. Doesn't explode.

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  Red canister. Doesn't explode.

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  Propane canister. Doesn't explode.

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  Blue gas can. Doesn't explode.

Explosives

Environmental explosives that can also be detonated with bullets.

• 

  Explosive barrel, has the largest explosion.

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  Red gas can. Ignites enemies, deals low damage.

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  Propane tank. Ignites enemies, deals low damage.

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  Butane can, introduced in Episode Two.

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  Ditto, alternate model.

Useful items

Also includes every single weapon and ammunition. All health/armor pickups are based on the 100 point limit.

• 

  Supply crate. Can be destroyed faster than with the crowbar.

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  Medkit.

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  Health vial.

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  HEV Suit battery.

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  Emergency flare, introduced in Episode One. Ignites when picked up. Can ignite enemies during its 30 second fuse until it burns out.

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  An Energy Ball. Can be picked up in the Citadel or if a Combine Elite fires one. Will vaporize any enemy it touches.

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  Car battery, used in a puzzle along the Coast.

Organic variant

When exposed to the Confiscation Field in the Citadel, the Gravity Gun is "supercharged", rather than being vaporized as Gordon's other weapons are. This also cripples the field itself in the process. Once supercharged, the Gravity Gun emits blue light rather than orange, shakes in Gordon's hands, and creates electrical arcs across its front. Its powers are vastly enhanced, enabling it to manipulate objects of far greater mass than it could normally (such as Combine interfaces), as well as pull and repel them with greater force. Its most significant enhancement is its ability to manipulate organic matter. Any Overwatch unit pushed by its primary fire is instantly killed, and their body retains an energetic charge, shaking the body, and killing others if it strikes them. If grabbed by the gun's secondary fire, they are likewise killed instantly.

The first time the Gravity Gun is supercharged is in Half-Life 2’s thirteenth chapter, Our Benefactors, when Gordon's Prisoner Pod deposits him into a Confiscation Field; it remains supercharged until the end of the game. At the start of Episode One, it is no longer supercharged, but becomes supercharged again after Gordon and Alyx re-enter the Citadel to stabilize the core, when 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.

In Half-Life 2, the supercharged Gravity Gun's primary fire has the same fire rate as the normal version. This is not the case in Episode One, where it can be fired as fast as the trigger is pulled.

Related Achievements

Any Half-Life 2 game
	Bone Breaker (5G)
	Kill 30 enemies with thrown physics objects.
	Deadly Harvest (5G)
	Kill an enemy by planting a Hopper Mine.
	Hack Attack! (5G)
	Kill five enemies with a Manhack.
	Hot Potat0wned (10G)
	Kill a Combine soldier with his own grenade.
	Conservationist (5G)
	Kill five enemies with the same Energy Ball.
	Think Fast! (10G)
	Kill an Elite Soldier with his own Energy Ball.
Half-Life 2
	Zero-Point Energy (5G)
	Get the Gravity Gun in Black Mesa East.
	Two Points (2G)
	Use Dog's ball to make a basket in the scrapyard.
	Zombie Chopper (25G)
	Play through Ravenholm using only the Gravity Gun.
	Flushed (5G)
	Kill an enemy with a toilet.
	Atomizer (10G)
	Disintegrate 15 soldiers by throwing them into a Combine ball field.
Half-Life 2: Episode One
	Grave Robber (5G)
	Steal a Zombine's grenade.
	Zombie-que (5G)
	Use flares to light 15 Zombies on fire.
	Car Crusher (5G)
	Use the cars to squash 15 Antlions in Episode One.
	The One Free Bullet (40G)
	Finish the game firing exactly one bullet. Grenade, crowbar, rocket, and Gravity Gun kills are okay!
Half-Life 2: Episode Two
	Grave Robber (5G)
	Steal a Zombine's grenade.
	Puttin' On a Clinic (15G)
	Defeat the chopper in Episode Two without any misses.
	Payback (10G)
	Kill a Hunter with its own flechettes.

Behind the scenes

• In an interview with RetroGamer magazine, David Speyrer stated that Jay Stelly had built an in-game tool, originally dubbed the "Physgun", that allowed the developers to pick up props and reel them in or push them away with an energy beam. This device would eventually evolve into the Gravity Gun.

• During Half-Life 2’s development, the Gravity Gun had several names, including: "Zero-Point Gun" or "prototype physics manipulator".

• As heard in sound files featured in the Half-Life 2 leak files, Eli was to explain to Gordon at Black Mesa East, that while Black Mesa was a "decade away from harnessing the zero-point energy field", it turned out that the Combine had already pioneered this technology. He then explains that the Gravity Gun is based off "a little piece of tech Alyx liberated on one of her expeditions". He also calls the Gravity Gun's secondary fire mode "asymmetric". The Gravity Gun's "grand daddy" was used to manipulate hazardous materials in the Combine's portal reactors, suggesting the Gravity Gun used Combine technology.

• At some point during Half-Life 2’s development, Ravenholm was set at the end of the Canals, and preceded Black Mesa East. Consequently, it didn't include the Gravity Gun, and as such, its gameplay only focused on Father Grigori's intricate traps (hence the name being used at that time, "Traptown").

• The Gravity Gun bears a vague resemblance to the Anti-Mass Spectrometer from Half-Life, notably the prongs. The Aperture Science Handheld Portal Device from the Portal series has some similarities as well; it was actually originally based on the design of the Gravity Gun, as seen in early Portal screenshots. It retained the prongs in the final design, as well as a zero-point energy field manipulator (also used by Fetchbot), allowing it to pick up small objects, but not launch them like the Gravity Gun.

• The Gravity Gun can be seen in the Enrichment Center lab where Doug Rattmann and Henry are working prior to GLaDOS killing its inhabitants, in the comic Portal 2: Lab Rat. Interestingly, in that same comic panel, we can also see two Black Mesa health and energy chargers, as well as what seems to be a Combine health charger. Marc Laidlaw confirmed that these were placed as a tribute to Half-Life, and nothing more.

Trivia

• When the player dies using the supercharged Gravity Gun, it disintegrates.
• Despite being arguably Half-Life 2's main weapon, outside of the game's ending sequence in the Citadel, the only times it is actually required to be used is to disable the three generators in the Overwatch Nexus. The Gravity Gun tutorials in Black Mesa East's scrapyard can be skipped by just waiting during the the punting tutorial, climbing up using other props in the area to knock over the barrels that Alyx wants you to grab with the Gravity Gun in the grabbing tutorial, and either waiting or stacking up props without the Gravity Gun to reach Alyx in the stacking tutorial.
• The Gravity Gun seems to be quite heavy, as Alyx Vance and other characters that attempt to use the gun have some trouble lifting it. It also has significant recoil, as demonstrated when Alyx uses it to push a train door away.
• Ravenholm was built around the use of the Gravity Gun, as it contains most physics elements seen during the series. One of its early names is "Phystown".
• The film District 9 features an alien weapon influenced by 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.

Gallery

Pre-release

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  HUD icon.

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  Ditto.

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  Physgun viewmodel.

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  Earliest Physgun viewmodel from the 2023 repository leak.

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  Early viewmodel from the the 2016-2017 Half-Life 2 leak.

Retail

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  The Gravity Gun stored in its cupboard at Black Mesa East.

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  Alyx opening the Gravity Gun's cupboard.

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  Alyx waiting for Gordon to take the Gravity Gun.

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  The Gravity Gun being supercharged in the Confiscation Field.

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  Ditto, after the transformation.

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  Killing Combine soldiers with the supercharged Gravity Gun.

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  Holding an Energy Ball in front of Combine soldiers with the supercharged Gravity Gun.

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  The Gravity Gun being taken away by a Combine Elite before Breen's office.

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  The Gravity Gun being held by the Combine Elite.

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  A Combine Elite carrying the "supercharged" Gravity Gun to Breen's office.

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  A Combine Elite handing the "supercharged" Gravity Gun to Breen.

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  Breen grabbing the Gravity Gun.

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  Breen escaping from his office with the Gravity Gun.

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  Wallace Breen talking to an Advisor with the Gravity Gun on the floor.

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  Ditto.

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  Magnusson Device being held by the Gravity Gun.

HUD icons

• 

  HUD icon, from "HalfLife2.ttf".

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  HUD pickup icon, from "HalfLife2.ttf".

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  Unused HUD icon for when a player picks up an object with the Gravity Gun in Half-Life 2: Deathmatch, from "HalfLife2.ttf".

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  HUD icon used when a player is killed by an object thrown with the Gravity Gun in Half-Life 2: Deathmatch, from "HL2MP.ttf.

Models

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  Viewmodel.

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  Worldmodel.

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  Supercharged viewmodel.

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  Supercharged worldmodel.

Other

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  The Gravity Gun in Portal 2: Lab Rat.

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  Gordon carrying the Gravity Gun next to Alyx in promotional art made for Half-Life 2’s 20th anniversary.

List of appearances

Combine OverWiki has more images related to Zero Point Energy Field Manipulator.

Main games

• Half-Life 2 (First appearance)
• Half-Life 2: Episode One
• Half-Life 2: Episode Two

Other

• Half-Life 2: Deathmatch (Non-canonical appearance)
• Half-Life 2: Raising the Bar (As "prototype physics manipulator")
• Half-Life 2: Lost Coast (Non-canonical appearance)
• Source Particle Benchmark (Game files only) (Non-canonical appearance)
• Portal 2: Lab Rat (Non-canonical appearance)
• The Final Hours of Portal 2