The player controls a square avatar whose quest is to explore an open-ended environment to find a magical chalice and return it to the golden castle.

While not the first such Easter egg, Robinett's secret room pioneered this idea within video games and other forms of media, and since has transcended into popular culture, such as the climax of Ernest Cline's novel Ready Player One and its film adaptation.

In Adventure, the player's goal is to recover the Enchanted Chalice that an evil magician has stolen and hidden in the kingdom and return it to the Golden Castle.

The kingdom is guarded by three dragons—the yellow Yorgle, the green Grundle, and the red Rhindle—that protect or flee from various items and attack the player's avatar.

Level 1 is the easiest, as it uses a simplified room layout and does not include the White Castle, bat, red dragon, or invisible mazes.

[10] Robinett was finishing his work on Slot Racers when he was given an opportunity to visit the Stanford Artificial Intelligence Laboratory by Julius Smith, one of several friends he was sharing a house with.

There, he was introduced to the 1977 version of the computer text game Colossal Cave Adventure, created by Will Crowther and modified by Don Woods.

[13] The final game uses nearly all of the available memory (including 5% of the cartridge storage for Robinett's Easter egg),[17] with 15 unused bytes from the ROM capacity.

[13] Robinett credits Ken Thompson, his professor at University of California, Berkeley, with teaching him the skills needed to use the limited memory efficiently.

[18] Robinett first identified ways to translate the elements of Colossal Cave Adventure into simple, easily recognizable graphics that the player interacts with directly, replacing text-based commands with joystick controls.

[13] Robinett developed workarounds for various technical limitations of the Atari 2600, which has only one playfield and five memory-mapped registers available to represent moving objects.

Finally, he used the registers assigned for missiles, such as the bullets in Combat, for additional walls in the playing field to be able to represent different rooms within the game with the same playfield.

[19][10] Another hardware limitation forces the left and right sides of nearly every screen to be mirrored, which fostered the creation of the game's confusing mazes.

They are mirrored, but contain a vertical wall object in the room to make an asymmetrical screen, as well as provide a secret door for an Easter egg.

[10][23][24] When Robinett developed a working prototype within one month, Atari's management team was impressed, encouraging him to continue the game.

[13] Instead, Atari developer John Dunn agreed to take Robinett's prototype source code to make the 1979 Superman game.

Robinett found that the various possibilities that arose from this combination of elements improved the excitement of the game, and subsequently made three dragons, reusing the same source code for the behavior of all three.

[27] Generally defined as a "message, trick, or unusual behavior hidden inside a computer program by its creator", the Easter egg concept was popularized by Adventure, influenced by the corporate culture at Atari.

After Atari's acquisition by Warner Communications in 1976, there was a culture clash between the executives from New York, and the Californian programmers who were more laid back.

After the game was released, Adam Clayton, a fifteen-year-old from Salt Lake City, discovered it and sent a letter of explanation to Atari.

[22] Atari eventually decided to leave the access mechanism in-game, and dubbed such hidden features "Easter eggs",[34] saying they would be adding more such secrets to later games.

This causes the barrier on the right side of the screen to blink rapidly, and the player avatar is then able to push through the wall into a new room displaying the words "Created by Warren Robinett" in text which continuously changes color.

"[42] Bill Kunkel and Frank Laney in the January 1981 issue of Video called Adventure a "major design breakthrough" and that it "shatters several video-game conventions" such as scoring and time limits.

[43] The 1982 book How to Win at Home Video Games called it too unpredictable with an "illogical mission", concluding that "even devoted strategists may soon tire of Adventure's excessive trial and error.

[44] Atari Headquarters scored the game 8 of 10, noting its historical importance while panning the graphics and sound, concluding that Adventure was "very enjoyable" regardless of its technological shortcomings.