Easter eggs

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This page contains a list of Easter eggs featured in the Half-Life and Portal series. Many are in-jokes, pop culture references, or simply hidden gags to reward curious players.

Half-Life and expansions

Half-Life

Chapter(s)	Map(s)	Description	Images
Anomalous Materials	c1a0, c1a0d, c1a0a, c1a0b	Nameplates with the surnames of several Half-Life developers are on the locker doors in the locker room. Several nameplates created are left unused. The Black Mesa Announcement System will also call out the names of several developers throughout the chapter.
Anomalous Materials	c1a0d	Gordon Freeman's locker contains a couple of Easter eggs: a photo of a baby, and two books. According to Harry Teasley, the baby in the photo is his and Yatsze Mark's daughter, Isabel Teasley. The photo was originally placed "in a ruined office in another level, on a broken desk". It was later moved to Freeman's locker by another designer, most likely Brett Johnson (whose locker is next to Freeman's), the creator of this map. The photo was also accompanied by a since-cut nameplate with Isabel Teasley's name. The two books, The Orchid Eater and The 37th Mandala, are real world books written by Marc Laidlaw. A texture for another book of his, The Third Force, was also created, but ultimately left unused.
Anomalous Materials	c1a0d	The PlayStation 2 port adds an audio gag involving the two scientists occupying the toilet stalls in the locker room, conversing with one another utilizing pre-existing science team quotes in a humorous manner. While there are three normal exchanges that play at regular intervals, a secret fourth exchange is scripted to play once every five minutes.
Anomalous Materials, Unforeseen Consequences	c1a0a, c1a1	The very small text on the Black Mesa Security Force advertisement reads: "If you can read this shit then you are really fuckin strange... with good eyeyeS" and "I need text of interest here. no really go ahead and picture something cool in your minds eye make something up of what you would like for this to say".
Unforeseen Consequences	c1a1b	The entity name of the single Alien Slave encountered in this chapter, found breaking down a closet door, is "georgeclinton". George Clinton is an American funk music artist.
Office Complex	c1a2, c1a2b	Outside their respective offices, the nameplates for doctors Newell and Van Buren can be seen, referencing Gabe Newell and Bill Van Buren, respectively. An unused nameplate for Sgt. Harrington, a nod to Mike Harrington, was also created, but ultimately left unused.
On A Rail	c2a2c	The name "Riller", made out of brushes, can be found on a wall hidden beneath a stairwell. Dave Riller built the underground train system and is likely the designer of this map.[i]
Various	Various	The text on the back of the Gun-Nut ammo boxes reads: "I'm just a crazy ol' kill-your-schoolmates kind of guy! Why dontcha join me in a spree?".[i]
Various	Various	An issue of a newspaper called The Onion can be found among the gibs of destroyed trash cans. The Onion is a real world satirical digital media company and newspaper organization.[i]
Various	Various	One of Valve's logos can be seen on a coffee machine outside the walk-in freezer in chapter Office Complex, on map c1a2c. Valve's logo also can be found on back of HEV Suit and on unused texture for a portable toilet.
N/A	boot_camp, crossfire, doublecross, frenzy, snark_pit, subtransit, thehill, undertow	Dario Casali's signature, made out of brushes, can be found in every multiplayer map made by him.

Half-Life: Opposing Force

Chapter(s)	Map(s)	Description	Images
Boot Camp	ofboot0	The first initials and surnames of several Opposing Force developers can be found on the footlockers in the dormitory. This is a nod to the similar Easter egg in the Half-Life and will become a recurring joke throughout the series. The creator of the map David Mertz's footlocker is next to Adrian Shephard's, just as Brett Johnson's locker is next to Gordon Freeman's in Half-Life.
Boot Camp	ofboot0	By enabling "noclip", the player can access an otherwise unreachable room below the dormitory that contains the signature "D M M 1999". "D M M" are the initials of David Michael Mertz, the creator of the map, with "1999" being the release year of Opposing Force.
Welcome To Black Mesa	of1a1	The room with the CT scanner has a computer with a sonogram on its screen. This an ultrasound image of Randy and Kristy Pitchford's son, Randall Steward Pitchford III.
Welcome To Black Mesa	of1a1	At the security checkpoint is a computer, that, when used three times, crashes and gives the Blue Screen of Death.
Friendly Fire	of2a4	By enabling "noclip" near the beginning of the map, the player can access an otherwise unreachable room outside of the playable map used for entities, with a message on its wall reading: "What are you doing in my entity room?".
Friendly Fire	of2a4	Two dead scientists can each be found lying in front of their respective desks in an office. The nameplates on their desks read "S. Reardon" and "S. Jones", nods to Gearbox employees Sean Reardon and Steve Jones.
Friendly Fire	of2a5	In another office, a photo of a developer's babies can be found in an overturned file cabinet.
We Are Not Alone	of3a1	Shooting the vent cover opposite the blast doors in the hallway leading to the Lambda Complex's portal room 25 times will result in the vent cover in the ceiling breaking and dropping a Chumtoad.
We Are Not Alone	of3a1	Using the Displacer Cannon in this map transports the player to a ruined version of the Hazard Course from Half-Life. In one of the observational rooms is a photo of Rob Heironimus (taken by co-worker John Faulkenbury) from Easter, 1998 with plastic Easter egg shells over his eyes.
Vicarious Reality	of4a3	In the specimen room where the Barnacle Grapple can be found is an empty, broken glass case labeled "007". This is a reference to James Bond and his ability to escape any situation he's trapped in.
Pit Worm's Nest	of4a4	The puzzle to kill the Pit Worm requires both a "gearbox" and a "valve" to be activated, which are obvious references to the game's developer and publisher, Gearbox and Valve, respectively.
N/A	N/A	In the game's "misc" folder is an unused sound file called "dsbossit.wav". When played normally, it sounds like a garbled voice speaking gibberish, but when reversed, reveals the phrase "To win the game you must kill me, Randall Pitchford", referencing the final boss of Doom II that similarly states "To win the game you must kill me, John Romero" backwards. Randall "Randy" Pitchford and John Romero were the lead developers of Opposing Force and Doom II, respectively. In addition, "dsbossit" is the same filename used for its equivalent in Doom II. This Easter egg was voiced and added into Opposing Force by Gearbox programmer John Faulkenbury.

Half-Life: Blue Shift

Chapter(s)	Map(s)	Description	Images
Living Quarters Outbound	ba_tram1	Beneath the tram tracks at the beginning of the game is a soccer ball, the model of which was taken from the Team Fortress Classic map Push.
Living Quarters Outbound	ba_tram1	During the tram ride, a security guard and a scientist can be seen playing a fighting arcade video game titled Prax Wars 2: Dante's Revenge. This is a reference to Prax War, a canceled video game by Rebel Boat Rocker, the key members of which would later found Gearbox Software.
Insecurity	ba_security2	As with Half-Life and Opposing Force, nameplates with the surnames of several Blue Shift developers are on the locker doors in the locker room.
Insecurity	ba_security2	Barney Calhoun's locker in the locker room contains a few Easter eggs: Immediately visible are two photos on the inside of the locker door, and two fictional books titled The Truth About Aliens by RH (Rob Heironimus) and Government Conspiracies with an illegible author and publisher logo. If the cardboard box inside the locker is shot at 68 times with the 9mm Pistol, using all of the ammo that can possibly be acquired on the map at this point, it will break and reveal a Chumtoad.
Insecurity, Captive Freight	ba_security2, ba_teleport1	Rob Heironimus's Easter egg photo from Opposing Force can be found inside a toilet stall in Insecurity, and later inside an air duct in Captive Freight.
Insecurity	ba_security2	Interacting with the camera surveillance system will show Gordon Freeman arriving at the Anomalous Materials Lab, and Gina Cross pushing the sample on the delivery cart. After viewing the first surveillance camera multiple times, one of the scientists Freeman passes will break out into dance.
Insecurity	ba_security2	The very small text on this Black Mesa Security Force advertisement reads: "Yes, these men are fine examples of natural born man killers. Black Mesa employs nothing but the best!".
Duty Calls	ba_canal1	The computer with the ultrasound image of Randy and Kristy Pitchford's baby from Opposing Force can be found in the flooded lab.
Captive Freight	ba_yard3	A box can be found that has fallen open down a set of stairs, with its contents, a few gears, strewn across the floor. This is literally a "gear box", a nod to Gearbox Software.
Captive Freight	ba_yard3	Sean Reardon's nameplate from Opposing Force is sitting on a desk in the room where Harold is found. In the same room, a photo of a developer's baby can be found on the inside of a locker door.

Half-Life: Decay

Mission(s)	Map(s)	Description	Images
Domestic Violence	ht05dorms	Repeating the trend, nameplates with the surnames of several Decay developers label each dorm room in the Level 3 Dormitories (excluding Gordon Freeman).
Domestic Violence	ht05dorms	The book The Truth About Aliens by RH that previously appeared in Barney Calhoun's locker in Blue Shift can be found in Gordon Freeman's room.
Domestic Violence	ht05dorms	A dead security guard is floating in the dormitory pool. When the guard's corpse (which has 3,000 health, more than Decay's final boss) is destroyed (therefore requiring 600 crowbar hits), it is scripted to explode and spawn a Snark pickup.
Intensity	ht11lasers	At the very beginning of the map, shooting the button to the players' immediate left within five seconds of loading the level will make Richard Keller say a humorous alternative introductory conversation line.[i]
Rift	ht12fubar	After defeating the final boss, switching to Colette Green's perspective will briefly show a sparking computer. Its electrical arcing paths, if connected together by imaginary lines, will reveal the stylised signature of Matt Armstrong.

Half-Life 2 and Episodes

Half-Life 2

Chapter(s)	Map(s)	Description	Images
Point Insertion	d1_trainstation_01	The name of Wright Bagwell, a former Valve employee, can be seen on a clock face in the City 17 Trainstation.
Point Insertion, Anticitizen One	d1_trainstation_02, d3_c17_02	The doll model seen in the playground appears to be based on a mutilated doll from The X-Files episode Born Again.
Point Insertion	d1_trainstation_04	When Alyx and Gordon first meet, she asks him "Doctor Freeman, I presume?", likely referencing the famous quote "Dr. Livingstone, I presume?".
"A Red Letter Day", Black Mesa East, Entanglement	d1_trainstation_05, d1_eli_01, d3_c17_01	Near a desk at Kleiner's Lab can be seen two crates marked as radioactive. One of them is yellow and bears the words "PLUTONIUM HANDLE WITH CARE". This is a reference to the plutonium case featured in the movie Back to the Future. The same desk model was used in Black Mesa East.
"A Red Letter Day", Black Mesa East, Entanglement	d1_trainstation_05, d1_eli_01, d3_c17_01	A photo of Mark Twain can be found in Kleiner's Lab on a desk. The same desk model was used in the surveillance room at Black Mesa East.
"A Red Letter Day", Black Mesa East, Entanglement	d1_trainstation_05, d1_eli_01, d3_c17_01	On a security workstation in Kleiner's Lab can be seen a CD player indicating the name "Blue Scholars", which is the name of an alternative hip-hop band. One of its two members, Sabzi, is the cousin of Dhabih Eng, one of the designers of the location. On the same workstation can be seen a radio tuned to FM 89.50. KNHC, also known as C89.5 FM, is a music station run by students at Nathan Hale High School in Seattle, Washington. It can be heard in a small radius around Puget Sound, but also streams live to the Internet.
"A Red Letter Day", Entanglement	d1_trainstation_05, d3_c17_01	A console in Kleiner's Lab displays the text "42FF". It was placed by Gary McTaggart, a former Valve programmer, and is a reference to a friend group called "42 Freedom Fighters" that he is a part of.
Black Mesa East	d1_eli_01	Eli's Lab at Black Mesa East contains a number of Easter eggs: several fictional and one real world book can be found on a bookshelf. The head of a Cremator, an enemy cut from the final game, can be found in a jar nearby computer screen with a scan of the object. The G-Man's face can be seen at the yellow end of one of the units manned by the Vortigaunt.
Sandtraps	d2_coast_11	The names of the Vortigaunts conversing in Vortigese at the Vortigaunt Camp are Dum and Dee, which is a reference to the Tweedledum and Tweedledee characters in an English nursery rhyme and in Lewis Carroll's Through the Looking-Glass.
Anticitizen One	d3_c17_08	Apparently referencing the Super Mario series, this map features a narrow corridor with three metal pipes and a Headcrab set to move back and forth between two of them; it is instantly killed when touched by the player.
Various	Various	The alphanumerics "V952" can be seen on several Combine devices, including the Combine Sentry Gun, the Emplacement Gun, the Hunter-Chopper, the Hunter-Chopper Bomb, and the Overwatch Standard Issue Pulse Rifle. The textures for these models were created by Tri Nguyen; "V952" is the badge number of his brother, who is a police officer in Ottawa, Canada.
Various	Various	The number "24724" can be seen in a graffiti. It is the ZIP Code for Freeman, Mercer County, West Virginia.
N/A	N/A	The real world book Nineteen Eighty-Four by George Orwell is among the trash in the Half-Life 2 texture garbage001a_01.vtf, but remains unused in the final game. This is one of the more direct references to the author's work in the game.
Various	Various	Graffiti seen frequently throughout the game features Russian text alongside an image of lemons and oranges being bombed. This is an inside joke made by Valve level designer Matt Wood. The text "ДЕЙ", which actually says "DEY" in Russian, is actually meant to visually represent the English word "Ren", the nickname of his then-girlfriend who was said to be a vegetarian at the time. Therefore, the bombs dropping on the fruit jokingly suggests a hatred for them.
Various	Various	A headline reading "SIFF reviews" can be seen on a paper sheet texture, which appears to be a page about the Seattle International Film Festival.
Various	Various	When played backwards, Classic Zombie sounds reveal phrases, such as "Help, God, help! Help me!"

Half-Life 2 leak

• When first launched, the Valve Hammer Editor featured in the Half-Life 2 leak plays a 3 seconds MIDI intro of the song "U Can't Touch This" by MC Hammer (named "hamrtime.mid"), an obvious play on the name of the artist, and the infamous sentence featured in the song, "Stop... Hammer time!".

• There is a line^[i] that was to be said by a security guard in a port of the Hazard Course from the original game. The line is: "Sorry, sir. You know I can't let you through here without your good friend Superfly Johnson. Wa hah. Just kidding, Gordon. You go on through. Hah haha!". Superfly Johnson is a character from the video game Daikatana, best known for his poor pathfinding skills. He is an ally, and has to follow the player through some levels. If the player reaches a loading point and the character is not with the player, the player character will say: "I can't leave without my buddy, Superfly!". It is also a reference to a line^[i] said by the security guard when Gordon tries to go through a checkpoint without his suit on. The line is: "Sorry, Mr. Freeman, I got explicit orders not to let you through without your hazard suit on."

Half-Life 2: Episode One

Chapter(s)	Map(s)	Description	Images
Undue Alarm	ep1_citadel_00	The "Modified bear" logo of the rock band Radiohead can be seen on the steering wheel of the car Alyx and Gordon use to enter the Citadel.
Urban Flight	ep1_c17_02a	The names of the developers can be seen on room signs in the Hospital.

Half-Life 2: Episode Two

Chapter(s)	Map(s)	Description	Images
This Vortal Coil	ep2_outland_04	There is an unreachable section of the Victory Mine's Antlion colony tunnels in which a message reading "How did you get back here?!" can be seen. This message will not be displayed if the "notarget" cheat is enabled.
Our Mutual Fiend	ep2_outland_11	In the White Forest base, an Easter egg referring to the TV series Lost can be found. In Uriah's lab, there is an inaccessible room containing a computer terminal with the six factors of the Valenzetti Equation shown on the screen and, on the wall, a Dharma-style octagon with the three pines from the White Forest logo in the middle. According to Steve Bond, many Valve employees are fans of Lost, and they noticed several strong Half-Life references in the first season of Lost. Gabe Newell and Lost creator J. J. Abrams exchanged e-mails, and Newell promised Abrams there would be a Lost reference in Episode Two, and this room was created.
Our Mutual Fiend	ep2_outland_11	The text on Episode Two's clipboard model texture uses excerpts from an article about rocket propulsion from the Rocket and Space Technology website created by Robert A. Braeunig.

Half-Life: Alyx

Chapter(s)	Map(s)	Description	Images
Is Or Will Be	a2_train_yard	Graffiti of the Aperture Science Sentry Turret can be found in Fairview Junction.

Portal series

Portal

Chapter(s)	Map(s)	Description	Images
N/A	N/A	An unused wet floor sign texture, humorously referencing the film 300 and the infamous meme "This is Sparta!" can be found in the game files. The texture file is located in the folder props_facemovie, while its corresponding model can be found in the Source Filmmaker files with a plain texture. It is based on a picture made no later than May 2007.
Various	Various	The keyboards seen in enrichment center offices have several letters highlighted. These letters can be rearranged to spell ASHPD, the acronym for the Aperture Science Handheld Portal Device as well as an abbreviation of Adrian Shepard. In the menu background seen after completing the game, there is a keyboard which has all letters of Adrian's name highlighted.

Portal 2

Chapter(s)	Map(s)	Description	Images
The Cold Boot	sp_a2_fizzler_intro	At the start of Test Chamber 08, the turbines of the Enrichment Center malfunction and GLaDOS has to temporarily leave, giving Chell only the "fast" version of the test's explanation, which is an incomprehensible sped-up sentence. When slowed down, the sentence reveals itself to be "and methodically knocking people’s hats off—then, I account it high time to get to sea as soon as I can.", an excerpt from Herman Melville's novel Moby-Dick.
The Fall	sp_a3_transition01	In one of the office sections in Test Shaft 09, there is a partially obscured doorway that leads to the empty dry dock of the Borealis. Life preservers bearing the ship's name can be found in the same room.
Various	Various	Karla, a minor employee featured on a poster in Test Shaft 09 and nicknamed "the complainer", is named after Jay Pinkerton's wife, Karla Pacheco.

Source SDK

• The icon used for Hammer's obsolete entities consists of what presumably is the head of Jay Stelly pasted on the bust of Fonzie from the TV sitcom Happy Days, with his trademarks thumb up and leather jacket. It was created by Dhabih Eng early during the development of the Source engine. The icon was updated for the Source 2 tools, using the same photo of Fonzie but a different one for Stelly.

• 

  The obsolete icon for Source.

• 

  The obsolete icon for Source 2.

• Typing the example coordinates "200 -4096 1154" into the "Go To Coordinates" dialog in Hammer results in a dialog appearing, which reads "Seriously? (I mean, that was just an example, you were supposed to type in your own numbers)".
• A line in the file sdk_weapon_parse.cpp from the 2013 edition of the Source SDK features a nod to Douglas Adams, author of the series The Hitchhiker's Guide to the Galaxy, and its number 42: m_iDamage = pKeyValuesData->GetInt("Damage", 42) // Douglas Adams 1952 - 2001.

See also

• The G-Man#List of exact in-game locations