Proto:Half-Life 2 (PC)

In October 2003, a hacker managed to break into Valve's internal network and steal a work-in-progress version of Half-life 2, which he then released on the internet as the 'Anon Beta' or 'Russian Beta.' Many interesting pieces of content that were cut from the final game are still present here, including a large amount of enemies and weapons. It is still floating around out there, and many websites have been created to pry it apart and expose its inner workings.

Cut Enemies and NPCs
DpnKPAL0CnY

Many of the cut/early enemies can been seen in action in this video.

Combine Assassin
Spawnable in the beta as npc_fassassin, this enemy is a remake of the female assassins found in the first game. The only map with one pre-placed is the fake e3_Gurluas. Interestingly, she sports a pair of heelsprings that were recycled for Portal.

Combine Guard
Spawnable as npc_combineguard, this hulking enemy carried a gun similar to a Strider cannon and was completely invincible. It was a trans-human enemy that was almost entirely mechanical, with the human face being the only sign that it was not just a robot.

Alien Assassin
Present in the files as npc_assassin, though entirely broken and unspawnable. Its behavior and animations resemble the Fast Zombie, suggesting that it is an early version of that enemy. There is also a zombie version of the Assassin, separate from the Fast Zombie.

Wasteland Scanner
Basically the same as the Retail scanners, but with rockets and an orange coloration. These were cut along with the Wasteland areas (a sample of which survived in the teleport sequence).

Cremator
An NPC that would've been seen cleaning the streets of bodies using a flamethrower called the Immolator. Like the Alien Assassin, it remains in the files but cannot be spawned in-game. Initially they would have been neutral, then switch to hostile during the Street Wars. Its head can be thrown using the Brickbat weapon, and the Immolator can be equipped using console commands. Though long gone by the retail release, its head can be seen floating in a container in Black Mesa East.

Hydra
A translucent enemy that would have been found in the sewers, where it would stalk Gordon and attempt to stab him with its deadly tentacles. It can be spawned as npc_hydra but only has idle animations and a few scripted actions intended for the E3 demonstration.

Bullsquid
Present in the first game, this enemy was also to appear in Half-Life 2 as an obstacle in the Route Kanal chapter. Two differently-colored texture files exist, but only one is used. Its spitting animation is unfinished, suggesting that it was cut fairly early.

Houndeye
Also present in the first game, these would have appeared in packs like wild dogs. While relatively docile and playful in their first appearance, years of wandering in an increasingly-barren world would have left them starving and ferocious, perfectly willing to hunt down humans if it meant their next meal.

Headcrab Zombie
The early Headcrab Zombie sports darker clothing and a more convulsed pose than the retail and, oddly enough, has no head underneath the Headcrab. The early Torso varient has the same color scheme and a fully-modelled head.

Fast Zombie
The Fast Zombie looks completely unlike the retail, but has the same behavior nonetheless. Oddly, when spawned in test maps relating to the Fast Zombie in particular, the console will print out "LEAP! GLIDE! LAND!"

Poison Zombie
The Poison Zombie is essentially finished, with only minor design tweaks yet to be done.

Headcrabs
Like the Poison Zombie, the Headcrabs are nearly identical to retail. The only notable difference is that the standard Headcrab has black legs and blood smeared around its mandibles.

Dropship
The early Dropship has two models in the game files. One is a pink-colored creature with no apparent holding compartment. When spawned in-game, however, a different model much closer to retail is used.

Strider
The Early Strider appears identical to retail, but has some very odd features. If the player uses noclip to reach its head and presses Use, the camera switches to the Strider's point of view. Once in this position, the only way to escape is to fire an RPG, which kills the Strider and drops an ERROR box that grants the player the Immolator when touched.

Gunship
The Gunship is identical to the Retail model, except it is able to shoot a blue beam from its underside.

Shield Scanner
The Shield Scanner is the same as in Retail, but it has animations related to attacking with its inside claw. It also has an unfinished, untextured shield model.

Combine Soldiers
There are texture differences in the basic Metrocop and Soldier models, but their behavior and animations are finished.

Stalkers
The Stalker is very aggressive and flighty in the beta, quite unlike the nearly-harmless retail version. It attacks the player with lazers and flees when approached or attacked, and if it is backed into a corner it will simply resort to battering the player with its arms. Design-wise, it appears more skeletal and sinister than in the retail and does not wear a loincloth.

Citizens
The earliest known model of a Citizen was found in a screenshot that came from the pre-beta map 'Get Your Free TVs!' It wears a gas mask, due to the foul air of the polluted Earth. In the playable Beta, they are wearing drab green clothes. There are also textures for the unused 'Stenographer's Chasm' workers and the Borealis worker model.

Child Workers
These workers were to be seen in the unused Combine Factories, producing Cremators. Not only were they cut when the Cremators were, but also due to the moral issues of having children in a FPS. The Cremator head they carry is part of the model, and the only animations they have are of putting them into machinery.

Cut Faces
These are various cut face textures found in the beta files. No matching models exist.

NPCs
While some NPCs remained mostly the same, others went through massive redesigns.

Captain Vance
Leader of the Conscipts. He was later merged with another character to become Eli Vance.

Mossman
Mossman had blonde hair, a different face, and the first name Helena rather than Judith.

Odell
Odell was intended to be the captain of the Borealis, but was cut along with his ship. His face was reused for Odessa Cubbage.

The Consul
Instead of Breen, the human face of the Combine was The Consul. All that remains of The Consul is an untextured statue.

Others
Other characters had their models changed between beta and retail as well.

The Crab and Mortar Synths
These two Synths are only briefly glimpsed in the Retail, found in the Citadel conveyor sequence and merely displaying walking/flying animations. However, in both the beta and Retail they have full attack animations.

Crab Synth
The Crab Synth is a large ground-based creature with charging animations.

Mortar Synth
The Mortar Synth is a flying creature that fires pulse beams.

Physgun
Re-used in Garry's Mod as an editing tool, the user can pick up NPCs and objects with it and manipulate them using the mouse.

Combine Guard Gun
Used by Combine Guards, it is very similar to the Strider's cannon.

FIM-92 Stinger
A missile launcher that functions exactly like the retail RPG.

GR9/HMG1
AKA the Heavy Machine Gun (HMG1). Has custom rounds.

Hopwire Grenade
A special grenade that, when thrown, sends out blue strands that stick to walls. When these strands are touched, the grenade explodes. Can crash the game in certain circumstances.

Immolator
This flamethrower was carried by the Cremators, and will set alight any NPC it hits. It has a green-colored beam that branches out at the end, and becomes stuck when fired for too long. It was powered with acid, and can also dissolve dead bodies.

Incendiary Rifle
A five-shot flaregun that can set enemies alight, but has a very short range. The weapon models and icons were recycled for the retail AR2 (a.k.a. OSIPR), as the model name ("irifle") kept this name.

MP5K/SMG1
Most likely the originally planned SMG. It can be spawned, but its viewmodel was removed and replaced by the retail MP7. NPCs can be seen using it and it works like the retail SMG, apart from its different clip size. Interestingly, if the player spawns a food package in the retail and picks it up, its menu icon will be the MP5K.

MP7/SMG2
A second SMG. This one holds more rounds than the MP5K, with three-round bursts and automatic firing. It has no worldmodel.

Sniper Rifle
This was re-used as an enemy weapon in Episode 2, also used occasionally by Alyx. It works as any Sniper Rifle would, and requires manual loading after each shot. Ammo for this weapon is still present in the retail files.

XM29 OICW/AR2
An early version of the AR2 Pulse Rifle. Instead of having an energy ball as the secondary fire, it has a scope and fires grenades. It has severe recoil after five shots, which can be minimized by crouching. There is an unused bayonet texture for it as well.

Brickbat
An odd weapon that allows Gordon to hold various objects in his outstretched hand, such as bottles, rocks and the Cremator's head.

Fire Extinguisher
A basic fire extinguisher. It can put out any naturally-occurring fires, even a burning NPC.

Flare Gun
Like the Incendiary Rifle, it shoots flares that can light enemies on fire from a very short distance. Ammo and the weapon itself can be found in pyrotechnic lockers in certain maps. Though all in-game Flare Guns are blue, textures exist for a red variation. There is also an odd set of textures for a disembodied arm holding a red flaregun.

Ice Axe
A crowbar clone. Can be swung faster, but is weaker. Its swinging sound was recycled for the retail crowbar.

Molotov Cocktail
A makeshift grenade that can light enemies and objects on fire when thrown.

AK-47/AR1
A very unfinished weapon with no animations or worldmodel, but can fire in different modes.

Sticky Launcher
Appears as a pistol, but fires sticky pink blobs that can be detonated with the secondary fire.

S.L.A.M.
Functionally identical to the tripwires in the first game. It was recycled for Half-Life 2 Deathmatch.

Stunstick
An electrically-charged club. It was recycled for use by the Metrocop units, then later in spinoff games.

Desert Launcher
wsfNxVSHvRE

Several pieces of heavy artillery exist in the beta, most only as 'brush' models and unusable. The Desert Launcher is unique in that it was fully animated and could actually fire at the player. The video shows it in action.

Jet Ski
The only operatable cut vehicle. Obviously, it was phased out in favor of the Airboat.

ZKXTQC92-Fc

Air Exchange Truck
A prop for the Air Exchange, an area that was axed during rewrites of the storyline.

Digger
An engineering machine intended for Ravenholm.

Submarine
Gordon and Odell were to depart from the Borealis on this Submarine. Once the Borealis was nixed, the Sub went with it.

Merkava
An Israeli combat tank that was to be used by the Conscripts, a group of low-ranking human Combine units lead by Captain Vance. Sound effects for it remain in the retail files.

School Bus
Intended to be used as the primary transport vehicle for Combine soldiers. It was replaced by the Dropships.

WC Mappack + Textures
There are hundreds of .VMF files in the WC Mappack, all at different stages of completion, with many duplicates. When run through Hammer, most maps can be compiled but will be missing textures and models. There are so many it's impossible to list them all here. The same situation is with the existing textures in game; there are dozens that never made it to retail.

E3 Demos + Early Storyline
In the beta are compiled maps used as technology demos at E3. In their native state, they are completely broken, but if edited in Hammer can be run without too much error. The folder also contains the original maps for the storyline, some complete, others running into dead ends or crashing.

Sound Files
Just as the textures, there are dozens of sound files never used in the retail. Some include full conversations, and many have generic voices that were to be re-recorded later. Several conversations in the retail version were shortened from the beta.