Adventure | Code Like It's 198x

In 1978 the text game Adventure needed more than 100K of memory on a mainframe. The Atari 2600 had 4K of ROM and 128 bytes of RAM, and when Warren Robinett told his boss he wanted to put the one on the other, he was told it was impossible. His Adventure kept the text game’s network of rooms, its objects to carry and its obstacles to get past, and drew them: one room to a screen, the objects as little shapes, the player as a plain square. It sold about a million copies. It also hid a room that Atari knew nothing about, with the words “Created by Warren Robinett” flashing across it.

Fast facts

Designer and programmer: Warren Robinett, who also drew the graphics, made the sound effects and drafted the manual.
Publisher: Atari.
Platform: Atari 2600, on a 4K cartridge.
Released: newspaper advertisements date it to March 1980; Robinett and Edge give 1979.
Inspiration: Will Crowther and Don Woods’s text game Adventure, now usually called Colossal Cave Adventure.
Sales: about a million copies, at $25 each.
Price: $31.95 suggested retail in Electronic Games’ 1983 buyers’ guide.

From text to pictures

Robinett played the text Adventure at the Stanford Artificial Intelligence Lab early in 1978, and he wanted to keep what he liked about it: “an interlinked network of rooms, which contained objects which could be carried from place to place, some of which allowed you to get past obstacles in the game”. Moving around a room became a matter of the joystick; going north became walking off the top of the screen. He defied his boss and built a prototype in about a month of 15-hour days, in which a player moved from screen to screen chased by a dragon. Marketing liked it enough to want a Superman game made from it; his colleague John Dunn took on Superman instead, and Robinett carried on with his own game. The Warren Robinett entry tells that story in full.

He took about a year over it, and halfway through he stalled. “It just wasn’t that interesting with a network of big open rooms, and a few dragons chasing you,” he told Retro Gamer. “At that point, there were no mazes, no bridge, no bat, and no magnet.” He put it aside for a few months to write the BASIC Programming cartridge, then came back and finished both.

Playing it

An evil magician has stolen the Enchanted Chalice, and the player must bring it back to the Golden Castle. The manual lays out the kingdom: three castles, gold, white and black, each locked by a gate that opens only with the key of its own colour, joined by rooms, pathways and labyrinths. You pick an object up by touching it, and drop it with the fire button. You can carry only one thing at a time.

The objects are the game’s tools. A sword slays a dragon when you touch the dragon with it. A bridge, laid across a wall, lets you pass over it. A magnet pulls objects towards it, which rescues a key you have dropped inside a wall. The three dragons each have a name and a job: Yorgle, the yellow dragon, is “just plain mean” and runs from the gold key; Grundle, the green one, guards the magnet, the bridge and the black key; Rhindle, the red one, guards the white key and is “the fastest Dragon and the most difficult to outmaneuver”. A dragon that catches you swallows you; the reset switch brings you back to life, though it revives any dragons you have slain as well. With the left difficulty switch at B, the dragons hesitate before they bite.

There are three games on the cartridge. Game 1 is a small kingdom with two castles and only Yorgle and Grundle. Game 2 is the full kingdom with all three dragons, dark catacombs and a black bat, which flies around carrying objects and swaps them for whatever you are holding. It might take your sword and leave you a live dragon, or take the chalice just as you reach the castle. Game 3 is the same kingdom with everything placed at random. Electronic Games, in a strategy guide in July 1982, warned that the randomness could put the gold key inside the gold castle, “and you think leaving your car keys locked inside the auto is bad!” The magazine’s 1983 buyers’ guide rated Adventure “Excellent” for play-action and “Outstanding” for solo play, with an overall rating of 9, and in Britain TV Gamer called it “arguably one of the best role-playing games to come from Atari”.

Fitting it into 4K

Robinett said later that the 2600 was “the weakest possible graphics engine on which you could actually build a videogame”: 4K of ROM for the program, graphics and sound together, 128 bytes of RAM, and “just two decent hardware sprites”. The design grew out of those limits.

One object at a time. Robinett first built an inventory screen, but stopping the action to look at it “didn’t feel right”. Limiting the player to one object meant the object could be drawn beside the player, so the game never had to pause. It also made the player choose: carry the key to open the castle, or the sword to fight the dragons?
A square hero. He kept the two good sprites for the objects and the creatures, so the player became a small square.
Mirrored mazes. The 2600 drew each room’s walls symmetrically, and Robinett was not sure at first that he could build confusing mazes from symmetrical pieces. He could. The mazes gave the bridge a reason to exist, and the keys that got lost in maze walls gave the magnet one.
Dark catacombs. To copy the text game’s dark caves, he made the maze walls the same colour as the background and put a large square object around the player, drawn between the two, so only a small patch of maze around the player showed. The lamp he first planned was dropped, because a player carrying the lamp could carry nothing else.
Creatures with minds of their own. Each dragon is a finite-state machine with four states that Robinett called Chasing, Biting, Swallowed-Man and Dead, and each creature has its own list of objects it moves towards or away from, which he called “desires” and “fears”. The creatures went on acting when they were off screen, and the bat’s habit of stealing your sword and leaving a dragon in its place “always got a laugh”, Robinett said. He named the bat Knubberub, a name that never reached the manual.
Flicker. When more than two objects are in a room, they flash, as the game takes turns drawing them with its two sprites.

Edge counted 30 screens in the finished game, and Robinett said he ended with 17 bytes of ROM to spare. He had tried to use the second joystick port to link two consoles so that two players could share the same world, and built a cable, but he was nearly out of memory and his boss did not want it. Marketing made one change: the Holy Grail he had planned became the Enchanted Chalice, for fear of offending customers with religious imagery.

Release and sales

The accounts differ on when Adventure reached the shops. Edge says “in time for Christmas 1979”, and Robinett gives 1979, but newspaper advertisements collected by the Atari Archive put it in March 1980. By then Robinett had left Atari. Edge reported that it sold a million copies at $25 each; Robinett had been paid a salary of $22,000 and received no royalties.

The secret room

Atari kept its programmers’ names off its boxes. Robinett put his on screen instead. In a sealed part of the black castle’s catacombs, reachable only with the bridge, a single grey dot sits against a wall, almost invisible. Carry it to a screen near the gold castle with two or more other objects, and the barrier on one side of the screen starts to flicker; the player can walk through it into a room with “Created by Warren Robinett” written down the middle. In Electronic Games’ words, “the programmer in question didn’t see fit to let his employer in on the joke”. When the room was found, he told Retro Gamer, “I didn’t work there any more by then. The other game designers were amused.”

Players found it. On 4 August 1980 a teenage player in Salt Lake City wrote to Atari that he had found “a dot” in the black castle, taken it to “the room by the gold castle”, and walked out of the kingdom into a room that said “Created by Warren Robinett”, which he drew for them. “Could you please comment on this,” he asked. (Edge later described the first finder as a 12-year-old boy from Salt Lake City; a note on the letter gives his age as 15.)

In December 1981 Electronic Games reported that “Sources at Atari have confirmed one of arcading’s most persistant wild stories”, and that Atari was “taking the whole thing with good grace”. It had given Atari’s Steve Wright an idea. “From now on,” Wright told the magazine, “we’re going to plant little ‘Easter eggs’ like that in the games. Eventually, we may have a real treasure hunt, with the clues hidden in various game cartridges!” A year later the hunt was a regular magazine feature. Electronic Fun with Computers & Games told its readers in December 1982 that “by now you probably know the famous Adventure quirk”, and how to fetch what it called the Transmolecular Dot in game 2. The British TV Gamer started its own Easter egg hunt in December 1983, printing Howard Scott Warshaw’s initials from Yars’ Revenge alongside Robinett’s room, and told its readers that Atari in America had flatly denied the rumours until it was sent a photograph.

Robinett’s room is the best-known early Easter egg, and his own website calls it the first. It is not the first known. The researcher Ed Fries found a hidden “Hi Ron!” message in Atari’s 1977 arcade game Starship 1, and Fairchild’s Video Whizball for the Channel F, from 1978, displays its programmer’s name.

Sequels and later life

Atari planned a sequel, and Retro Gamer reports that it grew into the Swordquest series, whose cartridges came with comic books full of clues for a prize competition. Robinett had nothing to do with it. In 2005 Curt Vendel wrote Adventure II for the Atari Flashback 2, a console with the 2600 games built in, reusing the original objects in a new set of rooms, and in 2007 Ron Lloyd and the AtariAge community released their own Adventure II for the Atari 5200. Compilations have kept the original in print, the Flashback 2 among them, with its manual reprinted inside.

The secret room reached a wider audience in Ernest Cline’s novel Ready Player One (2011) and Steven Spielberg’s 2018 film of it, in which a billionaire game designer hides an Easter egg of his own and the heroes finish their quest by finding Robinett’s room. In September 2025 Atari published Adventure of Samsara, a reimagining of the game by the Brazilian studio Ilex Games.

Sources

Adventure game program instructions (Atari), as reproduced by AtariAge (web): the Enchanted Chalice, the three castles and keys, the dragons and what they guard, the bat, the three skill levels and the left difficulty switch. https://atariage.com/manual_html_page.php?SoftwareLabelID=1
Atari Flashback 2 Owner’s Manual (Atari, 2005), pp. 25–27: the Adventure instructions reprinted, including Yorgle, Grundle and Rhindle, the bridge and magnet, and the three skill levels.
Electronic Games vol. 1 no. 1, December 1981, p. 14, “Hotline”: Atari confirms the secret message, the programmer who did not let his employer in on the joke, Steve Wright on “little ‘Easter eggs’”.
Electronic Games vol. 1 no. 5, July 1982, p. 34: strategy guide to Adventure’s three levels, the bat, “car keys locked inside the auto”.
Electronic Games 1983 Software Encyclopedia, p. 16: Adventure, $31.95, ratings and 9 overall.
TV Gamer, June 1983, VCS buyers’ guide: “arguably one of the best role-playing games to come from Atari”.
Electronic Fun with Computers & Games vol. 1 no. 2, December 1982: “the famous Adventure quirk” and the Transmolecular Dot.
TV Gamer, December 1983: the Easter egg hunt, the secret room, Atari’s denials, the Yars’ Revenge initials, the grey dot.
TV Gamer, June 1984, David Harvey’s guide to Adventure: Yorgle and Grundle in game one, Rhindle added in game two.
Edge issue 156, December 2005, “The making of Adventure”: Larry Kaplan, Stanford, the one-item inventory, the square and the sprites, desires and fears, the bat’s thefts, 30 screens, the Holy Grail and marketing, 17 spare bytes, the link cable, Christmas 1979, a million copies at $25, the $22,000 salary, the grey dot and flashing objects, the boy from Salt Lake City.
Retro Gamer issue 115, June 2013, pp. 72–75, “The making of: Adventure”: the rooms and objects he wanted to keep, “impossible”, the prototype and 15-hour days, a year’s work and the break for BASIC Programming, the mazes, bridge and magnet, the 2600’s limits, the one-object limit and the catacombs’ lighting trick, the dragons’ four states, Knubberub, the catacombs, “The other game designers were amused”, the link cable, Swordquest and the two Adventure II games.
A player’s letter to Atari, Inc., postmarked Salt Lake City, 4 August 1980, published by the Atari Compendium (web): finding the dot and the room. http://www.ataricompendium.com/game_library/easter_eggs/vcs/adventure_letter.pdf
Atari Archive, “Atari VCS game release dates” (web, secondary): March 1980, from newspaper advertisements. https://www.atariarchive.org/atari-vcs-game-release-dates/
Warren Robinett, warrenrobinett.com, Adventure page (web, secondary): published in 1979, a million copies, “the first Easter Egg”. http://www.warrenrobinett.com/adventure/
Ed Fries, “The Hunt for the First Arcade Game Easter Egg”, Kotaku, 24 March 2017 (web, secondary): Starship 1 (1977) and Video Whizball (1978). https://kotaku.com/the-hunt-for-the-first-arcade-game-easter-egg-1793593889
Ethan Gach, “The Real-Life Atari Secret That Inspired Ready Player One”, Kotaku, 30 March 2018 (web, secondary): the room in the film of Ready Player One. https://kotaku.com/the-real-life-atari-secret-that-inspired-ready-player-o-1824221173
Chris Scullion, “Atari launched its own Metroidvania on the same day as Silksong”, Video Games Chronicle, 9 September 2025 (web, secondary): Adventure of Samsara, Ilex Games, 4 September 2025. https://www.videogameschronicle.com/news/atari-launched-its-own-metroidvania-on-the-same-day-as-silksong-but-its-only-hit-12-concurrent-players-on-steam/